size of water line to run 3 or 4 self serve bays

[Scott.Downey]

We purchased an old wash (mid 80s ) with the premise that 2 of the 4 bays were not operational because of the lack of water pressure. the line that feeds the building is a 1 inch copper line that has 85 to 100 psi. is the line too small to feed another bay or was their another issue we should be looking at?

 

[Eric H]

I had some older SS washes with 2” water lines but the water meters were 5/8”. That means the water flow was the same as if the entire waterline was 5/8”. I never had an issue with flow.
I doubt you’ll have flow issues with a 1”line.
If you decide to install an IBA you may have issues but that is a discussion for another day.

 

[Randy]

85 - 100 psi is a little high, do you have a pressure reducing valve? My 5 bay S/S has a 1" water main, water pressure is around 45-50 psi. If you have a backflow preventor it will cut your water pressure down about 12 psi. I think you need to look at the water meter or at the water softener if you have one.

 

[Scott.Downey]

85 - 100 psi is a little high, do you have a pressure reducing valve? My 5 bay S/S has a 1" water main, water pressure is around 45-50 psi. If you have a backflow preventor it will cut your water pressure down about 12 psi. I think you need to look at the water meter or at the water softener if you have one.

i will look at the size of the meter tonight and also look for a backflow preventer. we also have a newer water softener.

 

[MEP001]

A 1" line should be plenty for a 6-bay wash with that pressure, but if that's just the static pressure and it drops with demand it could easily be too little. You'll need to put a gauge somewhere to see how bad the pressure drop is.

 

[Greg Pack]

1" line should be fine for a SS with no unusual restrictions. If you have a hose bibb put a pressure gauge on it and then force a float valve down. Ideally residual pressure in the lines would be 45 psi with water flowing, but as low as 25psi will work. Lower than that and you could have problems. Check for a partially closed valve. If all else fails you can boost the pressure yourself.

Also, look at the local fire hydrant. If they are color - red topped hydrants are indicative of poor water supply in the area.