Water Pressure, PRVs and Expansion Tanks in Gainesville, GA

01Your problem: fixtures keep leaking and the plumbing seems to be under strain

Some plumbing problems in Gainesville homes are not one broken part but a pressure problem that shows up in many places at once. A toilet that keeps running, an outdoor spigot that drips, or faucets that start leaking one after another can all point in the same direction. The City of Gainesville Department of Water Resources has published a short information sheet that explains why, and it is worth reading before you replace part after part.

The sheet says that in many areas of the county the pressure in the city's water main is over 100 psi, for the purpose of distribution and fire-flow protection, and that high water pressure can cause pipes to leak or break and fixtures such as faucets, spigots and toilets to leak because they are not designed to handle high pressures. The city provides the sheet for assistance and information only, and it frames the protection of household plumbing as the owner's responsibility from the back of the meter.

02Pressure-reducing valves

A pressure-reducing valve lowers the pressure from one side of the valve to the other. The city's example is a meter at 100 psi with the PRV keeping the home at 55 psi. The sheet says the national building code has required PRVs to be installed since 2000, that they are recommended but not required by the department, and that they go bad over time and need to be replaced periodically. A home built before that requirement may not have one.

The sheet lists where PRVs are usually found: in a box or buried on the house side of the meter, in a box or buried just before the pipe goes under the house, in the crawl space or just inside a basement wall where the line enters, or near the water heater. If you cannot find one, a plumber can check, and can measure the pressure with a gauge on a hose bib to tell whether the valve is doing its job.

03The meter's dual check and why expansion matters

The City of Gainesville installs dual-check backflow devices on water meters. The sheet explains that state and federal regulations require backflow devices on meters to protect the public water system, and that a dual check is a one-way valve that will not allow water to flow back from private plumbing through the meter. That protects the public supply. It also means water in your house has nowhere to go when it expands.

Water expands when it is heated. According to the sheet, heated water takes up a half gallon to a gallon more space in your plumbing and can increase the pressure by as much as 40 psi. With a closed system, that pressure has to be absorbed somewhere, and the city says that if you do not have a thermal expansion tank on your water heater, the dual check could affect the plumbing in your house. The backflow guide covers backflow devices from the permit side.

04Thermal expansion tanks

The sheet describes most expansion tanks as holding between 2 and 4 gallons, a little larger than a basketball, filled with air and divided by a rubber bladder. When pressure builds, the air compresses and the extra water moves into the tank. It should be located on the cold-water, or intake, side of the water heater. The city says the national plumbing code has required expansion tanks on all new homes since 1994, so homes built before then may not have one, and homes built after should have one, though there is no guarantee.

The department says it does not require homeowners to install an expansion tank or a PRV. It advises that these fixtures may or may not be part of your plumbing and that some investigation may be prudent. If you are replacing a water heater, this is the cheapest moment to add a tank, and the water heater guide covers the permit side of that job.

05Signs it is time to have pressure checked

The patterns that suggest high pressure are the ones the city's sheet describes: leaking faucets, spigots and toilets, and pipes that leak or break. A sudden drop in pressure is different; it can mean a failing PRV, a leak, or a problem on the city side. If pressure drops across the whole house and neighbors report the same, the department's directory lists the water and sewer repairs shop for pressure problems and leaks.

If pressure has been high for years, it is worth asking a plumber to check for leaks the pressure may already have caused. The leak detection guide explains the city's toilet dye test and how to read the meter with everything turned off, which is a good test to run before and after a PRV is adjusted or replaced.

06Getting a PRV or expansion tank installed

Installing a PRV or an expansion tank is plumbing work on your side of the meter. Inside Gainesville city limits, the building permit page lists plumbing upgrades, alterations or replacements among projects requiring permits, and asks owners to check with Building Inspections at 770-531-6570 if unsure. Ask the plumber whether a permit applies to your job. The permit guide explains which office handles your address.

The city's sheet suggests that owners either hire a licensed plumber to check the system or look for the expansion tank themselves. If you would rather have someone check it, send a Free Quote Request and choose Backflow, PRV or water pressure. Mention the age of the house and whether you have seen a tank near the water heater.

Which office handles the permit depends on where the house is. Hall County's page on city inspection departments says the cities inside the county, including Gainesville, Flowery Branch and Oakwood, have their own jurisdiction and inspection departments, and lists the City of Gainesville's at 770-531-6570. It adds that the City of Oakwood contracts with Gainesville's water and sewer department, so plumbing permits and inspections there are handled by the Gainesville inspection office. In unincorporated Hall County, the County's trade permit application packet covers plumbing trade permits and its residential plumbing fee page lists a water heater at $4.00, with a $35.00 minimum permit fee and a $35.00 re-inspection fee.