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.
The solution is very simple - install a pressure-reducing valve in the water main just after the meter and main shutoff valve. The valves are in the $100-$200 range from any commercial plumbing supplier (Home Depot probably doesn't have them).
High pressure
You can turn your internal stop tap (usually under your kitchen sink) down slightly to reduce the flow. You can also install a pressure reducing valve on your private pipework, which allows water to flow into it and reduces the pressure to a required setting.
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.
Adjust the Pressure
The regulator will have a screw or bolt and a locking nut system. Loosen the locking nut with a wrench and using quarter-turn increments, use a screwdriver to turn the screw counter-clockwise (to the left) to decrease water pressure, and clockwise (to the right) to increase water pressure.
Over time, mineral deposits and debris can build up inside your pipes, restricting water flow. This restriction forces the water to push through narrower passages, increasing pressure and potentially leading to leaks and burst pipes.
Locate the PRV, usually near the main water shut-off valve. Look for an adjustment screw on top of the valve. To increase pressure, turn the screw clockwise. Make small adjustments and retest the pressure after each turn.
Water Valves
Two main shut-off valves control the water flow in your home — one on or in your home and one at the meter. If one of these valves is partially or fully turned off for some reason, it can cause your water pressure to decrease considerably.
They will perform a thorough inspection of the meter to identify the source of the problem. Once identified, the plumber can replace the damaged parts or repair any malfunctioning components, such as the water meter valve, which will ultimately restore the water pressure.
Once you find the main water supply, turn it completely off. Turn all faucets to the 'on' position. Once the water supply is off (you might want to double-check this), turn all the faucets in your home to the 'on' position. This will allow for any trapped air to flow through the water lines.
A Pressure Reducing Valve (PRV) is a type of valve used to reduce the pressure of a fluid, typically water or steam, in its downstream line.
The key is to understand that negative pressure is caused by blockages in the pipes. These occur in the waste pipe o the ventilation pipe. The simplest approach to resolve the issue is to use a plunger in your toilet. It's important that you use a toilet plunger as this fits over the whole of the opening.
If your pressure is higher or lower, then you'll need to install, repair, or adjust your pressure regulator to comply. Adjusting your regulator is easy, as long as it's working properly. Simply tighten the screw down clockwise to increase pressure and counter-clockwise to decrease pressure.
For a standard PRV replacement, expect to pay around $400 to $800. This includes the new valve, plumber fees, permit charges, and any additional materials or labor.
Most houses don't have pressure reducing valves. Generally, the city or water district won't pump water to higher than 60 psi in your area (or have PRVs in their piping) - that would be wasted energy.
The required type of PRVs can cost anywhere from $90-$200 and can be purchased at a big box store. A plumber will charge anywhere from $200-$800 for materials and labor but a homeowner with a moderate level of maintenance knowledge might be able to switch out their PRV. Don't water utilities like WCID No.
The water pressure regulator is a bell shaped device often located on the main line inlet pipe, usually near the house shut-off valve (customer valve) outside the home.
A malfunctioning pressure regulator is one of the primary causes of too much pressure in your plumbing system. This device controls the flow and pressure of water entering your home. If it fails, the pressure can surge, leading to various plumbing issues.