top of page

Water Heater Inspection Checklist

The first, most obvious item checked during a water heater inspection is whether your water heater is providing hot water. But turning on the tap to see if hot water comes out is just a tiny part of a water heater inspection.

water heater replacement in Boston

Fuel Safety Inspection

A proper water heater inspection will evaluate its safety. The criteria differ based on fuel type. Water heaters generally rely on one of two power sources: electricity or gas (natural gas or propane). Each type comes with its own risks.


With a gas water heater, the two primary safety concerns involve fuel supply and venting. A water heater inspection should include checking the integrity of the gas lines and shutoff valves.

Gas water heaters require proper venting through a chimney or appropriate vent line. A thorough water heater inspection checks venting to ensure carbon monoxide won’t build up inside the home. Soot around the flue or vent often indicates a dangerous condition.

With electric units, a hot water heater home inspection should check for appropriate wiring size and connections. Proper circuit size and grounding are also important for safe operations.

Safe Water Tank Pressure

A water heater inspection will include checking the pressure relief valve on water heaters with tanks. A hot water tank is under a lot of pressure. Sometimes, that pressure can become too great.

The pressure relief valve vents off excess pressure to ensure the tank doesn’t rupture or explode. An inspection ensures the valve is functioning safely and not leaking.

Safe Operating Temperature

Another part of a hot water heater inspection involves checking the temperature of the water. It’s generally advised to set your water heater temperature to 120ºF to prevent scalding. This also saves on utility bills since it costs more to keep the water warmer.

Proper Installation

Both traditional water heaters with tanks and tankless water heaters have specific placement requirements. Water heater clearances vary by manufacturer. Your plumber knows where to find the specific requirements for your water heater installation.

Water Heater Suitability and Efficiency

To ensure you have hot water every time you turn on the tap, you need to be sure your water heater is the right size for your home. The methods for assessing water heater suitability vary depending on the type of water heater.

To determine the suitability of a tankless water heater, you must consider the temperature rise and flow rate you’ll need. First, count the number of hot water devices the water heater will serve (showers, dishwashers, sinks, washers, etc.).


You’ll need to know the flow rate for each hot water outlet. For instance, a standard showerhead uses about 2.5 gallons of water per minute. A modern dishwasher uses about 3 gallons per minute.

Next, you’ll need to check the water temperature rise of your tankless water heater. Most water enters the tankless unit at 50°F. For hot water that is 120°F, you’ll need a temperature rise of 70°F. To reach 104°F, as recommended for some dishwashers without heaters, it would be 90°F.

Most gas-fueled tankless water heaters can generate a 70°F temperature rise for flow rates up to five gallons per minute. Electric tankless units generate that temperature rise for flow rates up to two gallons per minute.

To rate a water heater with a tank, you need to consider its first-hour rating. That’s the number of gallons of hot water per hour the water heater can supply, starting with a tank full of hot water. New water heaters include this information on a label.


Next, determine your peak demand. Look at the time of day you use the most hot water. Then add up all the ways it’s used at the same time. This might be simultaneous showers while running the dishwasher each morning.

Add up the gallons of hot water you expect to use per hour during peak times. Then compare that to the water heater’s first-hour rating. You need a water heater with a first-hour rating within two gallons of your peak demand.

Provide a Repair Cost Estimate

If your water heater inspection reveals a concern, a professional inspector can determine the repairs needed and give you an idea of the cost. A licensed plumber should be able to include a water heater repair or replacement estimate with the inspection.

Annual Water Heater Inspection

Just like other major appliances, water heaters require regular maintenance. That includes both traditional water heaters with tanks and tankless water heaters.

All water heaters will benefit from annual flushing. Flushing your water heater helps remove minerals and sediment that can build up in the bottom of your water heater tank. Too much sediment can cause the water in the bottom of the tank to overheat, which stresses the unit.

Tankless systems require annual flushing to prevent limescale buildup and keep water flowing. If neglected, tankless water heater supply lines can clog.

Your plumber may include a free water heater inspection as part of your annual water heater maintenance visit. If not, ask for one. Even if it’s not free, the water heater inspection cost will be substantially less than the replacement cost.

Keep the Hot Water Flowing

When you’re buying a new home, you need to be sure everything is in working order. You don’t want unexpected repairs cropping up right after closing. And you don’t want to jump into your new shower only to find there’s no hot water.

It pays to have a professional hot water heater inspection before you buy. It can help ensure you have hot water every time you turn on the tap.

In Cambridge and the surrounding region, Minuteman Water Heaters can put your mind at ease. Contact us at 617-999-3249 to schedule your water heater inspection today.

bottom of page