Tankless Water Heater Installation Cost in Southern Maryland: 2026 Price Guide

By Gray & Sons Contracting · September 24, 2026

A tankless water heater installation in Southern Maryland costs $1,400 to $5,600 installed in 2026, depending on the fuel type, unit capacity, and the scope of infrastructure work required. Electric tankless units are the most affordable at $1,400 to $3,000 installed, propane tankless units run $1,600 to $4,500, and natural gas tankless units cost $2,100 to $5,600. Most homeowners in Calvert, St. Mary's, and Charles County pay between $2,500 and $4,000 for a professionally installed whole-house tankless water heater, including the unit, labor, permits, and any necessary gas line or electrical upgrades.

If you are reading this in September, you are in the right window. Fall is the ideal time to upgrade your water heater in Southern Maryland. The summer heat is fading, your contractor's schedule is more flexible than it will be during the holiday rush, and you have time to get the installation done and tested before the first cold snap drops your incoming water temperature from 70 degrees to 45 degrees. That temperature drop matters more than you might think with a tankless unit, because a tankless heater's real-world output depends on how much it has to raise the incoming water temperature. A unit that delivers a comfortable 8 GPM in July might only deliver 5 GPM in January when the groundwater coming through your well or municipal supply in Waldorf or Prince Frederick is 25 degrees colder. Sizing the unit for winter conditions rather than summer conditions is one of the most important details in getting a tankless installation right, and it is the kind of detail that separates a properly planned installation from a disappointing one.

This guide covers what a tankless water heater installation actually costs in Southern Maryland, how to choose the right unit for your fuel type and household size, what the installation involves, and what permits you need in Calvert, Charles, and St. Mary's County.

How Much Does a Tankless Water Heater Cost by Fuel Type?

The fuel type is the single biggest cost variable in a tankless water heater installation. It determines the price of the unit itself and, more importantly, the complexity and cost of the installation work behind the wall.

Electric Tankless Water Heaters: $1,400 to $3,000 Installed

Electric tankless units are the least expensive to buy, with unit costs ranging from $600 to $1,000 for a whole-house model. They are compact, require no venting, and produce no combustion gases. Installation is cleaner and simpler than gas or propane units because there is no flue to run, no gas line to size, and no condensate drain to install.

The catch is electrical demand. A whole-house electric tankless water heater draws 100 to 150 amps at peak demand, which is an enormous load. Most homes in Southern Maryland have 100-amp or 200-amp electrical panels. A 100-amp panel cannot support a whole-house electric tankless unit without a panel upgrade, which adds $2,000 to $4,000 to the project cost and often makes electric tankless the most expensive option overall despite the lower unit cost. Even with a 200-amp panel, you will likely need two to three dedicated 40-amp or 50-amp circuits run from the panel to the unit location, adding $250 to $900 per circuit.

For this reason, whole-house electric tankless installations are most practical in homes that already have a 200-amp panel with available capacity. If your panel is already full or you are still on 100-amp service, a gas or propane tankless unit is usually the more cost-effective path.

Electric tankless units do excel as point-of-use solutions. A small electric tankless unit installed under a bathroom sink or at a remote fixture where the hot water line from the main heater is long delivers instant hot water at that fixture and eliminates the wait time. Point-of-use electric tankless units cost $150 to $500 for the unit and $200 to $600 installed, and they draw far less power than a whole-house unit.

Propane Tankless Water Heaters: $1,600 to $4,500 Installed

Propane tankless units are the most common choice for Southern Maryland homeowners outside of the natural gas service areas. Natural gas is simply not available in much of the tri-county region. Washington Gas serves parts of Waldorf, La Plata, White Plains, St. Charles, and Indian Head in Charles County, and limited areas near Prince Frederick and Dunkirk in Calvert County. Outside those corridors, which includes most of Calvert County south of Dunkirk, all of St. Mary's County, and the rural portions of Charles County, your combustion fuel options are propane or oil. For a tankless water heater, that means propane.

If your home already heats with propane, you have a tank and a supply line infrastructure in place. The tankless water heater connects to the existing propane system with a dedicated line sized for the unit's BTU demand. Propane tankless units draw 150,000 to 199,000 BTU per hour, which is significantly more than a standard propane tank water heater at 30,000 to 50,000 BTU. The existing gas line from the tank to the house may need to be upsized, and the line from the house manifold to the water heater location almost certainly will. Gas line work adds $350 to $2,000 depending on the run length and whether the line goes through finished or unfinished space.

Propane tankless units also require sealed-combustion venting, either stainless steel Category III vent pipe through the roof or PVC concentric vent through an exterior wall. Direct-vent (through-wall) installations are simpler and less expensive than vertical venting, and most manufacturers allow horizontal vent runs of 10 to 25 feet, which provides flexibility in unit placement. Venting adds $200 to $800 to the installation cost.

For homeowners in Leonardtown, Mechanicsville, Hollywood, Lusby, Solomons, and the rural areas of St. Mary's and Calvert County who already have propane service, a propane tankless unit is often the best balance of performance, operating cost, and installation practicality.

Natural Gas Tankless Water Heaters: $2,100 to $5,600 Installed

Natural gas tankless units deliver the lowest operating cost of the three fuel types because natural gas is less expensive per BTU than propane or electricity in Maryland. The units themselves are the most expensive to purchase, ranging from $1,500 to $2,600, and the installation requirements mirror those of propane tankless units: a properly sized gas line, sealed-combustion venting, and a condensate drain for high-efficiency condensing models.

The key question for Southern Maryland homeowners is whether natural gas is available at your property. If you are in Waldorf near the Route 301 corridor, in La Plata, in White Plains, or in the St. Charles planned community, you likely have natural gas access. If you are in California, Lexington Park, Chesapeake Beach, Dunkirk, or most other Southern Maryland communities, you do not. Check with Washington Gas or your utility provider before assuming natural gas is an option.

For homes with existing natural gas service, the installation infrastructure work is the same as propane: the gas line from the meter to the unit needs to be sized for the tankless unit's higher BTU demand, and the old atmospheric vent from your tank water heater cannot be reused. Budget $350 to $2,000 for gas line work and $200 to $800 for new venting.

Tankless Water Heater Cost by GPM (Flow Rate)

Tankless water heaters are sized by flow rate, measured in gallons per minute (GPM), rather than by tank capacity. The GPM rating tells you how much hot water the unit can deliver simultaneously at a given temperature rise. A higher GPM rating means the unit can serve more fixtures at the same time, but it also means a higher unit cost and greater energy demand.

Sizing for Southern Maryland's climate. The GPM rating on the box is measured at a specific temperature rise, usually 35 degrees Fahrenheit. In Southern Maryland, your incoming water temperature varies seasonally. In summer, groundwater from a well in Calvert County enters the house at 65 to 72 degrees. In winter, that same water enters at 42 to 50 degrees. If you want 120-degree hot water (the standard setting), you need a 50- to 78-degree temperature rise in winter versus a 48- to 55-degree rise in summer. That higher winter temperature rise reduces the unit's effective GPM output by 20 to 40 percent.

A tankless unit rated at 9.5 GPM at a 35-degree rise might deliver only 5.5 to 6.5 GPM at a 70-degree rise. That is still enough for most three-bathroom homes in Waldorf or Prince Frederick, but it is a significant reduction from the headline number. Your installer should size the unit based on winter conditions, not summer conditions, and calculate the required temperature rise using local groundwater data rather than national averages.

How much GPM do you actually need? A standard shower uses 2.0 to 2.5 GPM. A kitchen faucet uses 1.5 to 2.0 GPM. A dishwasher uses 1.0 to 1.5 GPM. A washing machine uses 1.5 to 3.0 GPM. If your household regularly runs two showers and the dishwasher at the same time, that is 5.5 to 7.0 GPM of simultaneous demand. Size the unit for your realistic peak demand, not your average demand, because the moment the tankless unit cannot keep up is the moment someone gets a cold shower.

Installation Cost Breakdown

The unit price is only part of the total cost. Installation labor and infrastructure upgrades often equal or exceed the cost of the unit itself, especially when converting from a tank water heater to a tankless system for the first time.

Installation Labor: $600 to $2,500

Labor costs vary based on the complexity of the installation and whether you are doing a straightforward swap of one tankless unit for another or a first-time conversion from a tank system. A simple replacement of an existing tankless unit with a new one of the same fuel type takes 2 to 4 hours and falls at the lower end of the labor range. A full conversion from a 50-gallon electric tank to a propane tankless unit, which involves mounting the unit on an exterior or interior wall, running a new gas line, installing venting, connecting water lines, and removing the old tank, takes 6 to 10 hours and can stretch into a second day.

Licensed plumbers in Southern Maryland charge $85 to $150 per hour in 2026. For a project that involves both plumbing and gas line work, you may need two licensed tradespeople or a contractor who holds both plumbing and gas-fitting licenses.

Gas Line Installation or Upgrade: $350 to $2,000

This is the cost item that surprises most homeowners. A tankless gas or propane water heater draws three to five times as much fuel per hour as a standard tank water heater. The existing gas line from the meter or propane tank is often undersized for this higher demand, and the branch line to the water heater location almost certainly is. The plumber needs to calculate the total gas load of your home (furnace, range, dryer, fireplace, and the new tankless unit) and verify that the supply line, regulator, and meter can handle the combined demand.

If the main supply line is adequate but the branch line to the water heater is too small, the fix is running a new, larger branch line, which costs $350 to $800 depending on the length and routing. If the main supply line from the meter or tank needs to be upsized, the cost jumps to $800 to $2,000, and the work may involve trenching for a buried propane line or coordinating with the gas utility.

Old Tank Removal and Disposal: $75 to $500

Removing a standard 50-gallon tank water heater is a two-person job. The tank needs to be drained (30 to 60 minutes), disconnected from the water lines, gas line or electrical circuit, and vent, and then physically removed. A 50-gallon tank weighs 120 to 150 pounds empty and over 500 pounds full. Removal from a basement through a bulkhead or up a staircase is more labor-intensive and more expensive than removal from a first-floor utility room. Most plumbers include basic removal in their installation quote, but hauling the old unit away adds $50 to $150 if it is not included. If the old tank is in a tight space or a finished basement where removal requires disassembly or moving other fixtures, expect the higher end of this range.

First-Time Conversion vs. Replacement: Why It Matters

The cost difference between installing a tankless water heater for the first time and replacing an existing tankless unit is substantial. Understanding which category your project falls into helps you set a realistic budget.

Replacing an Existing Tankless Unit

If your home already has a tankless water heater and you are replacing it with a new unit of the same fuel type, the infrastructure is already in place. The gas line is sized correctly, the venting is installed, and the electrical circuits (for electric units) are already run. The installer disconnects the old unit, mounts the new one in the same location, reconnects the water, gas, and vent lines, and tests the system. This type of replacement typically costs $1,400 to $2,800 for an electric unit, $1,600 to $3,000 for propane, and $2,100 to $3,500 for natural gas.

First-Time Conversion from a Tank Water Heater

Converting from a traditional tank water heater to a tankless unit for the first time is a more involved project. The infrastructure changes are the reason. Your existing tank water heater uses a 1/2-inch gas line (or a 30-amp electrical circuit for an electric tank), an atmospheric vent through the chimney or B-vent, and floor space for the tank. A tankless unit requires a 3/4-inch or 1-inch gas line, sealed-combustion venting through a wall or roof, wall-mounting hardware, and possibly new water line connections in a different configuration. None of the existing infrastructure is reusable except the water supply and hot water distribution lines themselves.

First-time conversions in Southern Maryland typically run $2,500 to $5,600, depending on the fuel type, the distance from the gas supply to the installation location, and the venting complexity. The higher end applies to installations where the gas line needs to be run a significant distance, such as from an exterior propane tank on the side of a home in Mechanicsville to a basement wall-mount location 40 feet away.

Sample Project Scenarios

These three scenarios represent common tankless water heater installations in Southern Maryland. The costs reflect typical 2026 pricing including all materials, labor, and permits.

Scenario 1: Electric Tankless in a Waldorf Townhome

A couple in a two-bedroom, one-bathroom townhome in Waldorf is replacing a failing 40-gallon electric tank water heater. The home has a 200-amp electrical panel with available capacity. They choose a whole-house electric tankless unit rated for 5.5 GPM at a 60-degree rise, adequate for their low-demand household.

This is a best-case electric tankless scenario: a small home with adequate electrical capacity and a short circuit run from the panel to the installation location. The homeowners save roughly $100 to $150 per year in operating costs compared to their old electric tank, and they free up the closet space where the tank was sitting.

Scenario 2: Propane Tankless Conversion in a Lusby Single-Family Home

A family of four in a three-bedroom, two-bathroom home in Lusby is converting from a 50-gallon electric tank water heater to a propane tankless system. The home already has propane for the furnace and range, with a 500-gallon buried tank behind the house. The existing propane supply line is adequate for the total BTU load, but a new branch line is needed from the manifold to the water heater location on the basement wall. Incoming well water temperature drops to 45 degrees in winter, so they need a unit sized for a 75-degree temperature rise.

This project sits in the middle of the cost range for a first-time propane conversion. The family gains unlimited hot water (no more rationing showers before school), reduces annual water heating costs by roughly $100 to $200 compared to the old electric tank, and frees up floor space in the basement. The condensing unit runs at 95 to 98 percent efficiency, which maximizes the value of every gallon of propane.

Scenario 3: Natural Gas Tankless in a La Plata Colonial

A family of five in a four-bedroom, three-bathroom colonial in La Plata is replacing a 75-gallon natural gas tank water heater that is 14 years old and showing signs of internal corrosion. They have natural gas service from Washington Gas. Their plumber recommends a high-capacity natural gas tankless unit to handle the home's heavy hot water demand. The existing gas meter and main supply line can handle the additional BTU load, but the run from the gas manifold to the preferred installation location in the mechanical room requires a new 3/4-inch line through the basement ceiling.

This project exceeds the typical range because of the home's size and the scope of work involved. The large-capacity unit, the long gas line run through finished space, the heavy old tank removal, and the two-person crew all push the cost higher. However, the family eliminates the chronic problem of running out of hot water during their morning routine, saves $150 to $250 per year in operating costs compared to the old oversized tank, and extends the time before the next water heater replacement by 5 to 10 years. Over the unit's 20-year lifespan, the operating savings alone recover $3,000 to $5,000.

Permit Requirements by County

All three Southern Maryland counties require permits for tankless water heater installations. The permit ensures the installation meets the current Maryland Plumbing Code and any applicable mechanical or gas codes. Your licensed plumber or contractor should handle the permit application and schedule the inspection as part of the project.

What the inspector checks. The permit inspection verifies proper gas line sizing and connections, venting type and termination clearances, water line connections and shut-off valves, temperature and pressure (T&P) relief valve installation with a proper discharge pipe, combustion air supply (for gas and propane units installed in enclosed spaces), condensate drain routing (for condensing units), and electrical connections (for electric units). The inspector also confirms that the unit is accessible for future maintenance and that all work meets the current Maryland code requirements.

Do not skip the permit. A water heater installation without a permit is a code violation that can create problems during a home sale, complicate an insurance claim if the unit causes water damage or a fire, and result in fines. The permit fee of $50 to $200 is a small fraction of the project cost and ensures the work is done safely and to code. Any reputable plumber in Southern Maryland will pull the permit as a standard part of the job.

Hard Water and Tankless Heaters: A Southern Maryland Concern

Hard water is one of the most important factors to consider before installing a tankless water heater in Southern Maryland, and it is a factor that many homeowners overlook until problems develop. The relationship between hard water and tankless heaters is more significant than it is with tank water heaters, and understanding it upfront can save you hundreds of dollars in annual maintenance and prevent premature equipment failure.

Southern Maryland's geology produces well water that commonly tests between 7 and 25 grains per gallon of hardness, well above the 3.5 GPG threshold where scale begins to form inside plumbing and appliances. Homes on private wells in Huntingtown, Dunkirk, Solomons, Chesapeake Beach, Mechanicsville, and Hollywood frequently have hard water that will affect a tankless water heater's performance and lifespan if left untreated. Even homes on public water in Waldorf and La Plata can have moderate hardness levels that contribute to scale buildup over time.

Inside a tankless water heater, water passes through a narrow heat exchanger where it is heated rapidly from incoming temperature to the set point. Hard water minerals, primarily calcium carbonate, precipitate out of the water as it is heated and accumulate on the heat exchanger surfaces. This scale buildup reduces the heat exchanger's efficiency, forces the unit to work harder to achieve the same temperature rise, increases energy consumption, and eventually restricts water flow through the exchanger. Left unchecked, scale can permanently damage the heat exchanger and void the manufacturer's warranty.

Descaling. Manufacturers recommend flushing the heat exchanger with a food-grade descaling solution (white vinegar or a commercial descaler) every 12 months. On hard well water in Southern Maryland, every 6 months is more appropriate. Professional descaling costs $100 to $250 per visit. A handy homeowner with a descaling kit (a small pump and two hoses, approximately $100 to $200 to purchase) can do it in 45 minutes.

The better solution: treat the water. Installing a water softener or a whole-house water filtration system upstream of the tankless water heater dramatically reduces scale formation and extends the heater's life. If you are on well water in Calvert County or St. Mary's County and are investing $2,500 to $5,000 in a tankless water heater, adding a water softener for $800 to $3,000 protects that investment and reduces maintenance to an annual flush rather than a biannual one. Gray & Sons Contracting installs whole-house water filtration systems throughout Southern Maryland, and we frequently pair water treatment with tankless water heater installations for exactly this reason. A comprehensive water treatment and tankless heater project runs $3,500 to $8,000 combined, but the two systems work together to deliver clean, unlimited hot water with minimal long-term maintenance.

Is a Tankless Water Heater Worth the Investment?

The answer depends on your household's hot water demand, your current fuel setup, how long you plan to stay in the home, and whether you value unlimited hot water enough to pay the premium over a conventional tank.

When Tankless Is the Right Choice

A tankless water heater makes financial and practical sense when the circumstances align. If your household consistently runs out of hot water because you have four or five people taking showers in the morning, running the dishwasher during dinner, and doing laundry on weekends, a tank water heater forces you to stagger your hot water use or install an oversized tank that costs more to heat and maintain. A properly sized tankless unit eliminates that constraint entirely. You never run out of hot water because the water is heated on demand, continuously, for as long as you need it.

Tankless also makes strong financial sense when you are building a new home or doing a major renovation. In new construction, the infrastructure costs that drive up tankless installations in existing homes, new gas lines, electrical upgrades, venting, are already part of the construction budget. The incremental cost of a tankless unit over a tank unit is much smaller in a new-build context because the rough-in work is being done regardless.

If you plan to stay in your home for 10 years or more, the math favors tankless. A tankless unit lasts 15 to 20 years compared to 8 to 12 for a tank. Over a 20-year period, you buy one tankless unit or two tank units. The tankless unit costs more initially but eliminates the second replacement. Combined with annual energy savings of $100 to $200, the total cost of ownership over 20 years is often comparable, and you get the comfort benefit of unlimited hot water for the entire period.

Space savings are a practical advantage in smaller homes, townhomes, and condos throughout Southern Maryland. A tankless unit mounts on a wall and occupies roughly 2 square feet of wall space. The 50- or 75-gallon tank it replaces occupies 4 to 9 square feet of floor space. In a Waldorf townhome or a compact rancher in California, that reclaimed space has real value.

When a Tank Water Heater Is the Better Choice

A tank water heater is the better choice when you are doing a like-for-like replacement of a failed or aging unit and want to minimize cost. Replacing a 50-gallon electric tank with a new 50-gallon electric tank costs $1,000 to $1,800 installed, less than half the cost of a typical tankless conversion. If your hot water demand is moderate, your current tank size meets your needs, and your budget is tight, a quality tank replacement is a sensible decision.

A tank is also the practical choice when the infrastructure upgrades required for tankless push the project cost to a point where the payback period exceeds your time horizon in the home. If you are planning to sell in three to five years, the $3,000 to $5,000 premium for a tankless installation will not be recovered in the sale price. Homebuyers in Southern Maryland appreciate a tankless water heater, but the premium they will pay for one does not typically cover the full installation cost.

If you are on well water with very hard water and do not want to install a water softener, a tank water heater is more forgiving. Scale buildup in a tank reduces efficiency and shortens the tank's life, but the tank continues to function. Scale buildup in a tankless heat exchanger can restrict flow to the point where the unit error-codes and shuts down, leaving you with no hot water until the unit is descaled.

Tankless Water Heater Maintenance

A tankless water heater requires more active maintenance than a tank water heater, but the maintenance is predictable and, when kept up, extends the unit's lifespan well past the 15- to 20-year expected range.

Descaling is the most important maintenance task. On Southern Maryland well water, which tends toward hard, descaling every 6 months prevents scale from accumulating to the point where it affects performance. The process involves isolating the unit with the service valves, connecting a small circulation pump to the hot and cold service ports, running 3 to 5 gallons of white vinegar or commercial descaler through the heat exchanger for 45 to 60 minutes, flushing with clean water, and restoring normal operation. A descaling kit with a pump and hoses costs $100 to $200 and pays for itself after one use compared to professional service visits.

Inlet filter cleaning. Every tankless unit has a small mesh filter on the cold water inlet that catches debris before it enters the heat exchanger. This filter should be removed and rinsed every 6 months, especially on well water systems where sediment can clog the screen and reduce flow. A clogged inlet filter triggers a low-flow error code and shuts the unit down.

Venting inspection. Gas and propane units should have their vent termination checked annually for obstructions (bird nests, leaves, wasp nests, snow accumulation) and their vent connections checked for signs of corrosion or separation. A blocked vent is a safety hazard that can cause carbon monoxide to enter the home.

Energy Efficiency and Operating Cost Comparison

One of the primary reasons homeowners in Southern Maryland consider a tankless water heater is energy savings. Tankless units are inherently more efficient than tank water heaters because they eliminate standby heat loss, the energy wasted keeping 40 to 80 gallons of water hot 24 hours a day, whether you are using it or not.

Condensing vs. non-condensing. Gas and propane tankless units come in two efficiency tiers. Non-condensing units vent exhaust gases at 300 to 400 degrees and achieve energy factors of 0.82 to 0.87. Condensing units have a secondary heat exchanger that extracts additional heat from the exhaust gases before they are vented, cooling them to 100 to 130 degrees and achieving energy factors of 0.90 to 0.98. Condensing units cost $200 to $500 more than non-condensing units but recover the premium in energy savings within 3 to 5 years. They also produce acidic condensate that requires a drain line and a neutralizer, adding $100 to $300 to the installation. For Southern Maryland homeowners planning to keep the unit for its full 15- to 20-year lifespan, a condensing unit is the better investment.

The heat pump comparison. If you are currently on a standard electric tank and are considering a tankless electric unit, you should also evaluate a heat pump water heater. Heat pump water heaters cost $2,000 to $4,000 installed, qualify for a federal tax credit of up to $2,000 (bringing the effective cost to $1,000 to $2,000), and have the lowest operating cost of any water heater type. They require a space with 700 to 1,000 cubic feet of air (a basement or garage works; a closet does not) and work best in spaces that stay above 40 degrees year-round. For Southern Maryland homes with a suitable installation location, a heat pump water heater often delivers better value than an electric tankless, with lower electrical demand and lower operating cost. Gray & Sons Contracting installs both tankless and heat pump water heaters and can help you evaluate which technology is the right fit for your home.

Chesapeake Bay Area Climate and Your Tankless Water Heater

Southern Maryland's climate, shaped by the Chesapeake Bay and its tributaries, creates specific conditions that affect tankless water heater performance and installation planning.

Incoming water temperature. The Chesapeake Bay moderates air temperatures in the region, but groundwater temperature follows its own patterns. Well water temperature in Southern Maryland ranges from 52 to 55 degrees on an annual average, dropping to 42 to 50 degrees in January and February and rising to 65 to 72 degrees in July and August. Municipal water temperatures track similarly, though they tend to be slightly warmer in winter because treated water travels through pipes that are insulated from the coldest ground temperatures by urban infrastructure. Your installer should use the 42- to 45-degree winter low, not the annual average, when sizing your tankless unit.

Freeze protection. Tankless units installed on exterior walls with through-wall venting have water connections on the cold side of the wall. While the unit itself has built-in freeze protection (an electric heater element that keeps water in the heat exchanger from freezing), the water lines to and from the unit can freeze in an exterior wall that is poorly insulated. In Southern Maryland, where winter temperatures occasionally drop into the teens and single digits, your installer should insulate the water lines in the exterior wall cavity and consider a recirculation system or heat tape on exposed piping. This is especially important for homes along the bay and rivers in Solomons, Chesapeake Beach, and North Beach, where wind chill off the water drives effective temperatures lower than inland areas like Waldorf and La Plata.

Humidity and venting. Southern Maryland's high summer humidity does not directly affect the tankless unit's performance, but it can cause condensation on cold water pipes near the unit and on the vent termination during winter operation. Proper pipe insulation and vent termination placement (away from windows, soffits, and areas where condensation could cause ice buildup) prevent cosmetic and functional issues.

Frequently Asked Questions

How long does a tankless water heater last? A tankless water heater lasts 15 to 20 years with proper maintenance. The heat exchanger, which is the most expensive component, is typically warranted for 10 to 15 years by the manufacturer. With annual descaling and regular filter cleaning, many tankless units exceed the 20-year mark. The key variable in Southern Maryland is water quality, hard well water that is not treated with a softener or filtration system can shorten the heat exchanger's life to 8 to 12 years due to scale accumulation.

Can I install a tankless water heater myself? We do not recommend it. A tankless installation involves gas line work (for gas and propane units), electrical work (for electric units), venting through exterior walls or roofs, and plumbing connections. All three Southern Maryland counties require permits and inspections for water heater installations, and the permit requires a licensed professional. An improper gas connection is a safety hazard, an improperly sized electrical connection is a fire risk, and an incorrectly installed vent can allow carbon monoxide to enter the home. The cost of professional installation is a small fraction of the total project and ensures the work is safe, code-compliant, and covered by warranty.

Will a tankless water heater work with my well water? Yes, but you need to account for water hardness. Most well water in Southern Maryland is moderately to very hard, which means scale will build up in the tankless heat exchanger faster than in areas with soft water. You have two options: commit to descaling the unit every 6 months (DIY cost of $10 to $20 per flush, professional cost of $100 to $250), or install a water softener upstream of the tankless unit ($800 to $3,000 installed) to prevent scale formation in the first place. The water softener is the more effective long-term solution and also protects your other appliances, fixtures, and plumbing. Gray & Sons Contracting installs whole-house water filtration and softening systems and frequently pairs them with tankless water heater installations.

How much will I save on my energy bill with a tankless water heater? The savings depend on your current water heater type and fuel. Switching from a standard electric tank to an electric tankless saves $50 to $150 per year. Switching from a standard gas or propane tank to a gas or propane tankless saves $50 to $200 per year. Switching from an electric tank to a gas or propane tankless saves $100 to $250 per year. These savings compound over the unit's 15- to 20-year lifespan but rarely justify the higher upfront cost on their own. The primary reasons to choose tankless are unlimited hot water, space savings, and longer equipment lifespan rather than energy savings alone.

What size tankless water heater do I need for my home? For a one-bathroom home with one to two occupants, a unit rated at 5 to 6 GPM at a 60-degree rise is adequate. For a two-bathroom home with three to four occupants, target 7 to 8 GPM. For a three-bathroom home with four to five occupants or high simultaneous demand, you need 9 to 11 GPM. These recommendations are based on winter incoming water temperatures in Southern Maryland (42 to 50 degrees), not the manufacturer's standard test conditions. Your installer should perform a flow rate calculation based on your specific fixture count, household size, and usage patterns.

Do tankless water heaters work during a power outage? No. All tankless water heaters, including gas and propane models, require electricity to operate. The electronic ignition, flow sensors, control board, and combustion fan all need power. A tank water heater with a standing pilot light will continue to deliver hot water that is already in the tank during a power outage (though it will not heat new water if it has an electronic ignition). If power outages are a concern, and they can be in rural St. Mary's and Calvert County during storms, a whole-house generator provides backup power for the tankless unit and the rest of your home. Gray & Sons Contracting installs whole-house generators throughout Southern Maryland.

Can I switch from a tank to a tankless water heater without upgrading my gas line? It depends on the current gas line size and the total gas load on your system. In some cases, the existing gas supply line is large enough to handle the tankless unit's higher BTU demand, especially if the main line was originally oversized or if the home's total gas load is moderate. In many cases, the branch line from the manifold to the water heater location needs to be upsized from 1/2-inch to 3/4-inch or 1-inch. Your installer will calculate the total gas demand and determine whether the existing line is adequate before recommending upgrades.

Are there tax credits or rebates for tankless water heaters? High-efficiency gas tankless water heaters with a Uniform Energy Factor (UEF) of 0.95 or higher may qualify for a federal energy efficiency tax credit of up to $600 under the Inflation Reduction Act. Check the ENERGY STAR website for current qualifying models. Note that heat pump water heaters qualify for a larger credit of up to $2,000, which is one reason to evaluate both options before deciding. Maryland and local utility companies occasionally offer additional rebates, check with your utility provider for current offers.

How does a tankless water heater affect my home's resale value? A tankless water heater is a recognized upgrade that appeals to homebuyers, particularly in newer homes and homes marketed as energy-efficient. Real estate agents in Waldorf, La Plata, Prince Frederick, and Leonardtown report that tankless water heaters are a positive selling feature, though the added resale value typically does not cover the full premium over a tank installation. If you are installing a tankless water heater primarily to increase resale value, the return on investment is modest. If you are installing it for the performance and comfort benefits and plan to enjoy those benefits for several years before selling, the resale value is a bonus rather than the primary justification.

Ready to upgrade to a tankless water heater? Gray & Sons Contracting has been serving Southern Maryland homeowners for 50 years. We install tankless water heaters in Calvert, St. Mary's, and Charles County, and we handle everything from the initial assessment and unit selection to the gas line work, venting, permits, and inspection. Whether you are converting from a tank for the first time or replacing an existing tankless unit, we will size the system for your household, your water quality, and Southern Maryland's winter water temperatures so you get reliable hot water year-round. Get a Free Estimate