Hello Mr. Lamoureux,
We live in an HOA and our water pressure is very low. We had a plumber come out and he said, “The city is bringing it in at 55 lbs. of pressure which should be fine.” I don’t know if this is high or low but our shower pressure, especially upstairs, is very, very low. He also said some people take off the PRV and that this would help with the pressure. I don’t want to remove anything until I know it’s safe.
Once the water comes in from the meter through your PRV, pressure regulator valve, it will lose 7-8 pounds of pressure, and will drop another 7–8 pounds for every 8-10 feet of vertical run to reach your upstairs fixtures. So even though you’ve got 55 lbs. at the street, by the time the water reaches your upstairs showers, it’s down to about 40 lbs. of pressure.
The developer of your property knew how the grid was set up before they installed the PRV’s, so you’re home’s pressure was decided based on the existing amount of pressure from the city.
There are some people that remove the PRV, and this will give you another 7 pounds of pressure, but it is not something that I would recommend. If the city changes their grid and bumps up the pressure, you run the risk of coming home to a flood. They will not go door to door beforehand and alert homeowners of grid changes, and it is possible that the increase will blow out your flex lines to your sinks and washing machine, or ball-cocks on your toilets.
With commercial high-rise properties, there are pumps we install called jockey pumps. For residential, you could install a pressure pump with a bladder after your PRV valve. This will increase the pressure and would cost between $2200-$2800.
We just bought a house and have already discovered some sewage problems directly under the slab of the garage. I want to dig it up and replace about 40 ft. of line out to the main, but what’s the best way to get under the garage, which is 20 ft. long?
First of all, how deep is your sewer line? At my house it’s 17 feet deep. With 40 feet of excavation and shoring, you’re talking about a huge job.
I would start by calling a plumber with a camera to determine what the problem is exactly, and just replace what is necessary. While there, have them give you a proposal to saw-cut through your garage slab to make the repair, if that’s all that is needed.
If you do need to replace 40 feet of pipe that travels under your garage, I would leave the slab alone. Come back far enough from the garage that would allow you to put in some sweeps and go around the side of the garage, not under it.
Also, if a 40 foot replacement is necessary, a plumber will not be able to help you when you get to the city main. Only a sewage contractor is legally allowed to saddle into the main city sewage line.
Submit your questions to: firstname.lastname@example.org. Robert Lamoureux of IMS Construction, Valencia, CA, has 30 years experience as a commercial General, Electrical and Plumbing contractor. The opinions expressed in “Ask the Expert” are not to replace the recommendations of a qualified contractor after a thorough visual inspection has been made.