Water Pressure / PRV Service in Alpharetta, GA

When the relief valve on a water heater drips, or its discharge pipe leaves a puddle, the heater usually takes the blame. In many Alpharetta homes the real story involves two other parts working as a pair: the pressure-reducing valve on the incoming line and the small thermal expansion tank mounted near the heater. A proper pressure check looks at both, because a regulator doing its job perfectly can still cause spikes if the tank beside the heater has quietly failed.

How a working regulator creates a closed system

A pressure-reducing valve lets water into the house at a lower pressure, and many models let little or nothing flow back toward the street. A check valve or backflow device at the meter has the same effect. Each time the water heater warms a fresh tank, that water expands slightly, and in a closed system the extra volume has nowhere to go, so pressure throughout the house rises until a faucet is opened or the relief valve lets some out. The expansion tank exists to give that water a place to go.

What the expansion tank does and how it fails

Inside the tank, a rubber bladder or diaphragm separates water on one side from a cushion of compressed air on the other. As heated water expands, it pushes into the tank and squeezes the air instead of raising pressure everywhere else. Over time the air charge can leak down or the bladder can tear, and the tank fills with water. A waterlogged tank absorbs nothing. Two quick home checks:

• Tap the tank from end to end. A healthy tank sounds hollow over its air side and dull only near the water connection; one that is full of water sounds dull everywhere.
• Press the pin on the air valve briefly. Air is normal. Water means the bladder has likely ruptured.

Symptoms that point to thermal expansion

• The temperature and pressure relief valve drips, especially after a long hot shower or a dishwasher cycle.
• Pressure reads normal in the morning but noticeably higher after hot water use followed by a quiet spell.
• The first faucet opened after a lull gives a short burst of extra force.
• Toilet fill valves hiss or top up when no one has used them.

A dripping relief valve is a safety device doing its job, so it should never be capped or plugged. The useful question is why it keeps opening.

What the service involves

1. Static pressure is measured at a fixture downstream of the regulator, and a gauge with a max-reading needle is left on across a heating cycle when spikes are suspected.
2. The expansion tank is checked for a waterlogged bladder, and its air charge is read with a tire gauge once the tank is isolated or system pressure is relieved.
3. The precharge is typically set to match the house's static pressure, following the tank maker's instructions; a tank that will not hold air is replaced.
4. If the regulator lets pressure creep, it is adjusted, rebuilt or replaced, and the final setting is confirmed with the gauge.
5. The heater connections and the new work are checked for leaks once everything is back under pressure.

Sizing and mounting the tank

Expansion tanks come in several sizes, and the right one depends on the heater's capacity and the house's supply pressure; tank manufacturers publish sizing charts for exactly this. The tank usually goes on the cold supply near the heater and should be supported so its weight, once full, does not hang on the pipe. If the heater itself turns out to be the problem, the repair depends on its type: gas water heater repair and electric water heater repair are handled as their own jobs.

Who issues plumbing permits in Alpharetta

In Alpharetta, plumbing permits come from the Construction & Inspections staff in Community Development, the same office that handles building, electrical and HVAC permits. Ask that office whether replacing a regulator or adding an expansion tank at your address needs a permit before the work is scheduled.

Questions about expansion tanks and the PRV in Alpharetta

Does every house with a PRV need an expansion tank?

Not automatically, but a closed system is the usual reason a tank is installed. Model plumbing codes generally call for some way to control thermal expansion where a regulator, check valve or backflow device stops water from flowing back to the street. Whether your house needs one is best answered with a gauge reading across a heating cycle and the code your local building department enforces.

How long does an expansion tank last?

There is no fixed answer. The air charge slowly escapes, bladders age, and water conditions play a part, so a tank can fail well before the heater or outlast it. Rather than counting years, check it: do the tap test, look for rust or seepage at the fitting, and have the air charge read whenever the heater is serviced or the pressure is tested.

Can I just replace the dripping relief valve?

If the relief valve opens because pressure genuinely spikes, a new one will drip too, sometimes within days. Measure pressure across a heating cycle and inspect the expansion tank first. A relief valve that is corroded or leaks at normal pressure may need replacing as well, but that decision should follow the readings rather than stand in for them.

Call about a dripping relief valve

For a relief valve that keeps weeping or pressure that jumps after the heater runs, Alpha Plumbing and Sewer is a phone call away at (404) 409-4448. Let us know the heater's age and whether a small tank is mounted beside it.