The screw acts as a water pressure regulator. If you tighten the screw the water pressure will be more and if you loosen the screw the water pressure will be less. Turn the screw clockwise to tighten it and increase the pressure, or turn it counterclockwise to decrease the pressure. Do not be too hasty.
To reduce high pressure in a home, you'll need a Pressure Reducing Valve (PRV). In fact, these are often required by code for pressures beyond 80 psi. These devices do exactly what they say, reducing pressures of up to 400 psi down to a reasonable level of your choosing (most are factory set at 45 psi).
Water Pressure Readings
Normal water pressure is generally between 40 and 60 PSI. Most homeowners prefer something right in the middle around 50 PSI. Once you measure the water pressure in your house, you can adjust it to a setting that is ideal for all family members and household uses.
Normal water pressure range
In general, residential water pressure ranges between 45-80 psi (pounds per square inch). If your water pressure is under 40 psi, it's considered low. A psi between 20-30 is considered very low, and under the minimum water pressure required by most building codes.
On top of the regulator should be an adjustment screw and a lock nut. The adjustment screw raises and lowers the water pressure, but before it can be adjusted, you need to loosen the lock nut below it. Loosen the lock nut by half a turn with the crescent wrench.
A water pressure regulator is a dome-shaped brass fitting that is generally found just past the main shutoff valve, where the main water line enters the house. It usually has an adjustment screw on top.
If you're dealing with ongoing high water pressure, you should check on your regulator. You may be able to lower your water pressure by adjusting the regulator, or you might need to replace it with a new one. Older homes may not have been constructed with a water pressure regulator.
Do All Homes Have a Water Pressure Regulator? No, and in some cases, you may not need one. Certain municipal supplies regulate their water pressure safely, but if that pressure runs above 80 psi, you'll want to protect your plumbing system by installing one.
Where Can I Find It? No matter what kind of water heater you have, the pressure valve will be located either on the top or side of the unit. Most likely, it will be near the electric supply or hot water output tube.
Some of the first signs of a failing pressure regulator are a leaking water heater or commode. The water coming from a faucet may also exit with such force that splashing or water “hammering” may occur.
The short answer is low water pressure in your home arises due to a number of causes. Some include a shut or blocked water meter valve, mineral buildup clogs pipes, corroded pipes, or even a crack in the main city supply pipe to your home.
Loosen the lock nut on the pressure reducing valve with a wrench and back it off by unscrewing it. Fit a socket wrench over the adjustment nut on the top of the valve. Turn the nut counterclockwise to reduce the pressure downstream from the valve and clockwise to increase it.
A water pressure regulator, if you have one, is usually located where the main water line comes into the house and after the main shut off valve. This way if you need to work on or change the water pressure regulator you can simply shut off the water main to do so.
Fixing High Water Pressure
If your pressure is consistently above 80 psi, it's time to add a water pressure regulator to your waterline. Also known as a PRV (pressure regulating valve), the regulator does exactly what its name implies; it regulates the pressure in your plumbing system.
Most residential plumbing systems are designed to handle 40 to 60 PSI of pressure, with 80 PSI being the typical maximum and anything over 100 PSI being possibly detrimental to plumbing components.
Find the spigot closest to your source of water. Make sure all the taps and other water uses are turned off in your house. Now turn on the spigot and see how long it takes to fill the bucket. Dividing the number 60 by the time to fill the bucket will give you the gallons per minute number.
Standard home water pressure is designated as 80 psi, but when higher pressures are required to provide water for other facilities and services (often in the 100-110 psi range, but sometimes as high as 150 psi), this pressure can reach levels hazardous to your plumbing.
If your home receives water from the city lines, you most likely have a pressure regulator already installed. If you are uncertain whether your home has one or not, finding its location is simple. Locate the main shut-off valve of your home and look nearby. The PRV should be located directly next to the valve.
PSVs are activated automatically when pressure exceeds prescribed pressure limits in order to return equipment pressure to a safe operating level. A Pressure Relief Valve (PRV) is a type of valve used to release stored gas in various equipment in order to maintain an optimal pressure level.
Low water pressure can be caused by many things. Simple problems like the shut-off valve being closed or a faucet being blocked can cause low water pressure. More serious issues like plumbing blockage or water leaks decrease water pressure, too.