What Maintenance Does a Water Heater Need?

A water heater needs four routine maintenance tasks to reach its expected lifespan: annual tank flushing to remove sediment, anode rod replacement every three to five years to prevent tank corrosion, annual testing of the temperature and pressure relief (T&P) valve for safety, and (for tankless units) annual descaling. Combined, these add up to a few hours of professional service per year and can roughly double the useful life of a tank-style water heater.

At A.J. LeBlanc Heating, our licensed plumbers service water heaters across southern New Hampshire. Here is what each task does and why it matters.

1. Annual tank flushing (storage tank units)

Over time, sediment from the water supply settles at the bottom of a storage tank water heater. The buildup causes several problems:

• On gas units: sediment insulates the burner from the water, which reduces efficiency and overheats the bottom of the tank (a leading cause of premature tank failure).
• On electric units: sediment buries the lower heating element, which then burns out from operating without adequate water contact.
• For all tank units: sediment creates popping or banging noises during operation as water trapped under it superheats and escapes.

Flushing the tank once a year clears the sediment and is straightforward for a licensed plumber. NH homes on hard well water may need more frequent flushing.

2. Anode rod replacement every 3 to 5 years

The anode rod is the most important maintenance item on a tank-style water heater. The rod is a sacrificial piece of metal (magnesium, aluminum, or aluminum-zinc alloy) that hangs inside the tank and attracts the corrosive elements in the water. While the rod is intact, it corrodes instead of the steel tank. When the rod is fully consumed, the steel tank starts to rust through.

• Most anode rods last 3 to 5 years in NH water conditions
• Soft water, well water, and water with high sulfur or iron content wear rods faster
• Powered anode rods (which use a small electrical current instead of corrosion) last much longer and reduce hot water odor problems

Replacing the anode rod is one of the highest-payoff plumbing maintenance items a homeowner can have done. It can roughly double the useful life of a tank-style water heater. Most homeowners never have this done, which is why tanks routinely fail at 8 to 10 years instead of the 12 to 15 they could reach.

3. Annual T&P valve testing (all units)

The temperature and pressure relief valve is the safety device that prevents the tank from over-pressurizing in the event of a control failure. It is one of the most important safety devices in your home, and it can stick if it has not been operated in years.

• Lift the lever briefly once a year. Water should flow out of the discharge pipe and stop when you release the lever.
• If the valve will not open, will not close, or drips continuously afterward, replace it.
• The discharge pipe must terminate within six inches of the floor or at an approved drain. Never cap it.

4. Annual descaling (tankless units)

Tankless (on-demand) water heaters have heat exchangers that are sensitive to mineral scale buildup. Hard water shortens unit life and reduces efficiency if descaling is skipped.

• Annual descaling is recommended for most installations
• Homes on well water or with high mineral content may need it more often
• Tankless installations should include isolation valves on the hot and cold sides specifically to make descaling straightforward
• A whole-home water softener significantly extends the time between required descalings

Maintenance schedule summary

Things homeowners can do between professional visits

• Check for leaks: walk around the water heater quarterly looking for moisture, rust, or scale at the base, fittings, or relief valve
• Listen during operation: popping, banging, or rumbling usually indicates sediment buildup
• Check the temperature setting: typically 120°F for most NH homes (balances scald risk against bacteria suppression)
• Verify combustion airflow (gas units): keep the area around the unit clear of stored items

Warning signs that maintenance is overdue (or replacement is needed)

• Rusty or discolored hot water
• Rumbling, popping, or banging from the tank during heating cycles
• Rotten egg smell, especially on well water
• Visible moisture, rust, or scale around the base of the tank
• Reduced hot water capacity or longer recovery time
• The tank is past 10 years old

Schedule water heater service

For anode rod replacement, tank flushing, T&P valve service, tankless descaling, or a no-pressure conversation about replacement options, contact A.J. LeBlanc Heating. Serving New Hampshire families since 1928.

Frequently Asked Questions

How often should I have my water heater serviced?

Annually for tank flushing and T&P valve testing. Anode rod inspection every one to two years; replacement every three to five years. Tankless units add annual descaling.

Can I service my water heater myself?

Some tasks (visual leak inspection, T&P valve test) yes. Tank flushing is possible but involves draining the tank under pressure and handling very hot water. Anode rod replacement and tankless descaling are usually best left to a licensed plumber.

How long should a water heater last in NH?

A standard storage tank typically lasts 8 to 12 years; with consistent anode rod replacement and flushing, up to 15 years. Tankless units typically last 15 to 20 years; heat pump water heaters typically last 10 to 15 years with regular maintenance. Hard water shortens all of those numbers.

Why does maintenance matter so much for water heaters?

The tank itself usually outlasts the components inside it. Anode rod corrosion, sediment buildup, and scale on the heat exchanger are all preventable. Most tanks that fail at 8 to 10 years had no maintenance done.

What temperature should I set my water heater to?

120°F for most NH homes. Lower increases bacterial growth risk in the tank. Higher increases scald risk and accelerates anode rod consumption.