The two types of pressure
- There are two types of water pressure. Static pressure and flow pressure.
- Static pressure can be measured with a typical pressure gauge like measuring tire pressure. Static pressure is directly related to the elevation of the source of water in relation to the outlet. Static pressure is fairly constant and should be at 60-80 psi at the house. Static pressure is constant throughout the building and any other local buildings at the same elevation.
- Flow pressure is exactly what it sounds like. It is the velocity of the water coming out of the outlet. Flow is related to static pressure less any resistance the water encounters. Size and length of pipe reduces flow. Small orifices restrict flow. Blockages from small matter can really restrict flow. Opening many outlets at once can restrict flow. Modern piping is designed to handle many fixtures being used simultaneously without affecting pressure
How water pressure is created
- Community water districts create water pressure by raising the elevation of the water in a water tower. It gives the water column pressure. The pressure is created by gravity. So water pressure at the outlet i.e. your building is directly related to the elevation of the building and the elevation of the water source.
- Private wells store water in a holding tank that has a rubber bladder inside filled with air. The bladder gives the water its pressure since water does not compress well.
What causes low flow pressure
- Size and length of pipe restricts flow. Pipes that are undersized during construction or that have grown smaller from corrosion (galvanized steel pipe) restrict flow. These pipes may need to be replaced.
- Valves that are partially shut or that have particles clogging them restrict flow.
- Improperly set or faulty regulators can cause low pressure.
- A broken bladder in a private well’s holding tank will cause low pressure. The holding tank should be replaced . Seefixing a private well
Troubleshooting pressure problems
- If only one fixture has low flow it is either that a shutoff valve is turned low or that particles are clogging the valve. Remove the aerator at the end of the spout and clean or replace it. If that doesn’t help, disassemble the stems and flush out the valve. Seefaucet repair for instructions. If that doesn’t help replace the faucet or valve.
- If the entire building has low pressure, check the aerators. Also check the regulator, if you have one, it should be tightened to increase pressure. Check the main valve to ensure it is fully open. If a faucet flows quickly and then suddenly slows up, you know that a valve upstream needs to be fully opened.
- If you have always had low flow and you have cleaned your aerators, shower heads and valves, chances are that you need a repipe.
Fixing low flow problems
- Check aerators and shower heads and clean or replace them.
- If you find small white particles in your aerators it may be that the diptube in your water heater is disintegrating. For more info on diptube failurego to hot water runs out quickly.
- Faucet valves can become clogged and may need to be disassembled and cleaned. Seefaucet repair
- Check to be sure all valves are fully open
- Replace old galvanized pipes if they have become restrictive from corrosion.
Scalding Shower Solutions
- Turn down supply valves to toilet tanks to avoid toilets taking pressure from the shower.
- Install a pressure balanced shower valve that automatically compensates for pressure drops in hot or cold water.
Excessive water pressure problems
- Excessive water pressure can cause pipes to rattle or cause hoses and supply lines to burst.
- Static pressure should be 60-80 psi
- Install a regulator at the building supply to reduce pressure
- Install water hammer arrestors to eliminate water hammer