Whether you want to lower the water pressure for environmental reasons, or to make the water pressure higher, adjusting the water pressure in your house is actually not that complicated. Just follow the steps below.
Find the pressure-reducing valve. Locate the supply line coming into your house. The line and valve may be in the basement, crawlspace or the water meter box. The valve is brass and has a bell shape in the middle with a screw at the top of the bell. The screw is the adjuster.
Loosen the locknut by clamping it with the pliers or wrench and turning it counterclockwise as far as possible. This should make the screw adjuster accessible to turn.
To increase the water pressure in your house, use the screwdriver to turn the screw clockwise incrementally.
To decrease the water pressure, use the screwdriver to turn the screw counterclockwise incrementally.
Test your pressure after each incremental turn by turning on faucets and shower heads and flushing toilets. It may seem like a pain to test your fixtures after each tiny adjustment, but these small adjustments can make a lot of difference in the pressure. Too much pressure can damage your pipes and lead to leaks and water waste.
Once you have reached the proper water pressure, tighten the locknut once again and you're done.