My hot water relief valve is dripping
Every storage hot water system has a relief valve, the brass valve near the top of the tank with a small lever and a pipe running down to a drain outside. It's a safety device that lets out water if the temperature or pressure inside the tank gets too high. A few drips while the tank is heating can be normal. A steady drip all day, or water running out, isn't. Here's how to tell the difference and what to do.
Normal or not?
Usually normal
A small amount of water while the tank is heating, as the water expands. On many mains pressure systems a little discharge each heating cycle is expected.
Needs checking
Dripping all day and night, a steady trickle, or water running from the drain pipe. That's water and energy going down the drain.
Get it checked soon
Hot water or steam pouring out of the valve. That can mean the water is overheating and the safety valve is doing its job.
Why relief valves drip
- Worn valve: relief valves wear out. Many makers recommend replacing them about every five years.
- High mains pressure: if the pressure coming in is higher than the system is rated for, the valve lets water out to compensate. A pressure limiting valve or a new expansion control valve usually fixes it.
- Failed expansion control valve: many systems have a second valve on the cold inlet to handle expansion. When it fails, the relief valve takes the load.
- Overheating: a faulty thermostat can overheat the water, and the valve releases it. This needs attention soon.
- Grit in the seat: a bit of sediment can stop the valve closing properly.
What you can do
Most makers recommend gently lifting the easing lever on the relief valve every six months to let a little water out and keep it free. Lift it slowly, keep clear of the outlet as the water is hot, and let it snap back. If it keeps dripping afterwards, or the lever won't move, call a plumber. Never block the drain pipe or tie the lever down: the valve is there to stop the tank failing.
How we fix it
We check the incoming pressure, the expansion control valve, the relief valve and the thermostat, so we fix the cause and not just the symptom. Then you get a fixed price before any work starts. Usually it's a new relief valve, a new expansion control valve, or a pressure limiting valve.
In southern Eastern Suburbs homes
Mains pressure is high in many parts of Matraville, Botany, Pagewood and Eastgardens, and older homes often have no pressure limiting valve. That's one of the most common reasons we see relief valves running in this area.
Why locals call us
- Local to Matraville and the southern Eastern Suburbs
- Free on-site quotes, with a fixed price before any work starts
- Lifetime labour warranty on our workmanship
- 100+ five-star Google reviews
- Licensed plumbers and gasfitters (Lic. 398171C)
Common questions
Is it normal for a hot water relief valve to drip?
A little water while the tank is heating can be normal. Constant dripping or running water is not and should be checked.
Can I fix a dripping relief valve myself?
You can gently operate the easing lever to clear grit. If it still drips, the valve or the pressure control needs a licensed plumber.
How often should a relief valve be replaced?
Many makers recommend about every five years, and operating the lever every six months.
Why is hot water pouring out of my relief valve?
The water may be overheating or the pressure may be too high. Turn off the power or gas to the heater and get it checked soon.
Related help: hot water repairs, hot water servicing, pressure limiting valves, hot water too hot and water pressure guide. Local pages: hot water Matraville, hot water Botany, hot water Pagewood and hot water Eastgardens.