Why Low Pressure Happens And What You Can Do?
Gravity Drives Your Water System’s Pressure
The North Wales Water Authority’s distribution system is a gravity system. This means that the Authority pumps water from individual sources into a NWWA water tower which maintains an adequate level of pressure throughout our water distribution system. The water pressure experienced at any home within our system is solely determined by the elevation of that home relative to the elevation of our water tower.
Since NWWA relies on the force of gravity to deliver water to our customers, water pressure increases or decreases depending on how far a home is below the level of the water in the storage tank that serves that home. The farther a home is below the water level in the tank, the higher the water pressure will be in that home.
It is important to remember that vertical distance or elevation determines water pressure; physical distance from a storage tank does not. This is why customers with homes in low-lying areas experience higher water pressure than customers who live on the hilltops and ridges in our service territory.
Low Volume Water Problems
Most low-pressure problems are created in the home. In such cases, the home has adequate water service pressure, but pressure at fixtures drops off dramatically when another fixture is turned on. This situation is most commonly encountered when someone flushes a toilet when another person is in the shower. Usually the problem is that the water volume is lowered or restricted, therefore reducing the amount of water that comes out of the fixture. Here are some common causes of low water volume. You may have a combination of these problems.
1. Internal plumbing pipes are small
NWWA water arrives at your home in a 3/4″ or 1″ service line which can provide a lot of volume and pressure. But, in many homes, internal piping is only 1/2″ or less. This reduces the volume of water up to 75%, and unfortunately, can cut the pressure up to 75% as well.
2. Small pipes and a long way to go
In addition to smaller pipes (see #1), the problem is worse when water has to go up more floors or travel long distances. This often happens when an additional bathroom and fixtures are added to an older home, but the smaller pipe size is not upgraded. If you’re planning to remodel, be sure to have the water pipe diameter increased to an adequate size.
3. Devices that can affect the volume
Devices such as water softeners, water filters, flow restricting fixtures and decorative faucets can further restrict the volume of water flow in a home.
4. Pipe “arteries” are getting clogged
Rust and minerals can build up in older, galvanized plumbing and restrict the flow of water.
5. High on a hill
If your home is at a higher elevation, your water pressure may be below average. If it is below 40 pounds per square inch, a plumber can offer tips for increasing the volume of water to your fixtures.
What You Can Do
You may have one or a combination of problems. Our best advice is to talk to a reputable plumber. Use this information as a starting point and discuss each scenario. Usually your plumber can recommend solutions that can enhance your water volume.
Here’s a Glossary of Terms That May Help:
Water pressure: the force of water pushing on a unit area, usually measured in pounds per square inch (psi).
Static water pressure: water pressure, measured in psi, at the service line when there isn’t any water running.
Residual water pressure: water pressure at the service line when water is flowing.
Water volume: the amount of water that a pipe can supply. A 1/2″ pipe can only deliver a certain amount of water per minute regardless of water pressure.