Most homeowners have never heard of a pressure reducing valve, but it protects nearly every pipe, faucet and water appliance in the house. When it wears out, the damage often shows up somewhere else first: a dripping water heater, a burst washing machine hose or pipes that bang when you shut off the water.
Here's what this valve does, how long it lasts, and how to tell when yours needs attention.
What a pressure reducing valve does
Water often comes from the city at a higher pressure than your home's plumbing is built to handle. A pressure reducing valve (PRV) sits on the main water line where it enters your house, usually near the main shutoff valve. It lowers that incoming pressure to a safer, steady level before the water reaches your pipes and appliances.
Inside the valve, a spring and diaphragm do the work. They keep your home's pressure steady even when the city's pressure goes up and down during the day.
You'll usually find it:
- Near the main water shutoff, often in a basement, crawlspace or garage
- Sometimes outside near the water meter
- Shaped like a bell or cone on the pipe, often with an adjusting screw on top
Not every home has one. Many newer homes have a PRV, but some older homes don't. If you're not sure whether you have one, we can check.
What water pressure should your home have?
Most homes do well somewhere between 40 and 80 psi. Many plumbers like to keep it around 50 to 60 psi to go easier on pipes and fixtures. Most plumbing codes require a pressure reducing valve when the incoming pressure is over 80 psi.
How to check: A simple water pressure gauge screws onto an outdoor hose spigot and shows your pressure in seconds. You can find one at most hardware stores. If it reads over 80 psi, your PRV may not be working, or you may not have one.
How long does a pressure reducing valve last?
A PRV usually lasts about 10 to 15 years. Some fail sooner, especially when water pressure is very high or there's sediment in the line. If your home is more than 10 years old and the valve has never been checked or replaced, it's worth having it looked at.
What can go wrong
A PRV can fail in a few different ways:
1. It stops reducing pressure (fails high). This is the most common and the most damaging. The valve lets too much pressure through, and every pipe and appliance in the house feels it. You often won't notice until something starts leaking.
2. It restricts too much (fails low). Your water pressure drops. Showers feel weak, and it takes longer to fill a tub or a washing machine.
3. Pressure goes up and down. Water may surge, then weaken, or change when another fixture turns on.
4. The valve itself leaks. Look for water dripping from the valve or rust and mineral buildup around it.
5. Noise. Humming, whistling or vibrating near the main line can mean the valve is wearing out.
Signs your PRV may be failing
- Pipes bang or "hammer" when you shut off a faucet or the washer stops filling
- Your water heater's relief valve drips or discharges water
- Faucets drip or showerheads spray harder than they used to
- Toilets run or refill on their own
- Water pressure suddenly gets much stronger or much weaker
- Several fixtures or appliances start leaking around the same time
How high pressure affects your appliances
When a PRV fails high, the extra pressure puts strain on everything connected to your water. Over time, that can mean:
- Water heater: High pressure can make the temperature and pressure relief valve drip or open, and it puts extra stress on the tank. That can shorten the water heater's life.
- Washing machine: The supply hoses take the full pressure every time the washer fills. A burst hose can release a lot of water fast.
- Dishwasher and refrigerator ice maker: The small water lines and valves in these appliances can leak or fail early.
- Toilets: The fill valves can wear out faster, causing running toilets and higher water bills.
- Faucets and showers: The inside parts wear out sooner, leading to drips and leaks.
- Pipes and fittings: Constant high pressure and water hammer stress the joints. That can lead to small hidden leaks inside walls and floors.
Any one of these can turn into water damage, which is far more expensive than the valve.
A PRV and your water heater go together
When you install a pressure reducing valve, the water heated in your tank has nowhere to go when it expands. This is called thermal expansion. Without somewhere for that extra pressure to go, it can build up and make the water heater's relief valve drip.
That's why homes with a PRV usually need a thermal expansion tank near the water heater. The expansion tank gives that extra pressure somewhere to go. If your PRV is replaced or your water heater is replaced, it's a good time to make sure the expansion tank is working too.
Repair or replace?
Some PRVs can be rebuilt with a repair kit, especially if they're newer. Older valves, or valves with corrosion or leaks, are usually better off replaced. We'll check your pressure, look at the valve and give you an estimate before any work starts.
Have your water pressure checked
If you're seeing any of these signs, or your home has never had its water pressure checked, The Water Heater Heroes can help. We test your pressure, inspect your pressure reducing valve and expansion tank, and recommend what your home actually needs. We serve Metro Atlanta and offer same-day service.
Call (770) 641-9474 or request service online.