HVAC tech from Fort Worth, TX Got a buddy selling his house and the home inspector asked that the water pressure be raised from 55% to 60. Code is no higher than 65% so since I am doing some other minor fixes I wanted to see if someone could help me out and tell me if this is correct. Loosen the retainer, or lock nut, on the stem. Increase the water pressure by turning the pressure adjustment stem clockwise. Most manufacturers' pressure settings are 45-55 psi. Residential codes normally stipulate a limit of 50-70 psi. You won't be able to raise it beyond that standard.