How much does water pressure vary for municipal water supplies? I'm in the state of Washington, USA

[pa5tabear]

I've tried calling the city about this but I wasn't successful. I'll try again today and update.

 

[BigInch]

I'd say from 30 to 60 psig, but it probably has something to do with what city you're in, being in the middle of summer and little supply available, not to mention where you are on the distribution system.

Independent events are seldomly independent.

 

[77JQX]

Are you asking about various locations at a single time, or variation in pressure at a single location at various times? At the utility I work for, we want service pressures to be between 40 and 100 psi for all customers under all normal operating circumstances (fire flows and other emergencies excepted). For a normal individual location the pressure range depends on location - next to a pump station will see much greater variations than near a tank. Some customers see no variation throughout the year. I just checked some of our SCADA data to look for you, and the largest daily range I found (excluding transients) was about 20 psi. I consider a 15 psi change to be the threshold of what a normal residential customer will notice.

 

[cvg]

depending on the system design, pressure and variation could be highly variable or relatively consistent. If you want an accurate answer, you will need to take some measurements. suggest a gauge at the nearest fire hydrant

 

[bimr]

General guide:

"All water mains, including those not designed to provide fire protection, shall be sized after a hydraulic analysis based on flow demands and pressure requirements. The system shall be designed to maintain a minimum pressure of 20 psi (140 kPa) at ground level at all points in the distribution system under all conditions of flow. The normal working pressure in the distribution system shall be at least 35 psi (240 kPa) and should be approximately 60 to 80 psi (410 - 550 kPa) and not less than 35 psi (240 kPa)."

http://10statesstandards.com/waterrev2012.pdf