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tjfiles1975 · Jan 18, 2011, 11:49 AM

I live in a two story house that sits 350ft from the cities water main. My house sits higher in elevation to the main as well. I have had issues with what I thought was a water pressure issue for a while. The upstairs tub takes forever to fill and the shower is terrible as well. I had a tankless water heater installed and the gpm is barely enough to keep the heater lit. I had a plumber come and check my water pressure and he said I had 60psi at the outside spigot. I have 3/4 inch pipe supplying my house from the meter. What could be the problem and what are ways that I can fix this issue? I asked a plumber if increasing the size of water main would help and he didn't think so.

Milo Dolezal · Jan 18, 2011, 04:16 PM

Your problem is undersized water main pipe. You have adequate pressure (60psi) but you are lacking volume (delivery). Your house being elevated doesn't help it either.

Since you sit 350' away from the curb, I suggest that you install 2" pipe between street and house. But if possible, run it all the way through out the house and T off for each fixture with 1/2" or 3/4" branch.

But even that may not be enough. You may have to install a booster pump somewhere at the point where water pipe enters your house.

Hope that helps... Milo

jlisenbe · Jan 18, 2011, 06:20 PM

TJ, I'd do this. Buy a little pressure gauge that screws on to a hose bib, probably just what the plumber used. You will, I imagine, get a 60# reading, as he did. Now turn on a couple of faucets in the house. See what your pressure goes to. I'm going to guess it drops to next to nothing.

I used an online calculatore to figure your pressure drop in 3/4" pipe over 350 feet at 10 gpm and got 40# of loss. So Milo has hit it on pipe size. Not sure why you would need to go to 2" pipe IN the house. If you can get a good volume of water at good pressure to the house, then what you have in the house would be, I would think, sufficient. I'd sure try it first and see.

tjfiles1975 · Jan 20, 2011, 06:17 PM

The house had 50psi and I turned on another faucet it maintained 50psi. Have 3/4" meter and 3/4" line to house. House is plumbed with 3/4"copper sized down to 1/2" when going to fixture.

tjfiles1975 · Jan 20, 2011, 06:18 PM

Also wondered if I need to increase my meter to 1" (max they will allow me) when I increase my water line to 2" or leave it as a 3/4"?

jlisenbe · Jan 20, 2011, 07:11 PM

Pressure reading 60# with no water being used doesn't mean much, but with TWO faucets on, it held 50#? Well, I'm surprised. If pressure loss over 350' of pipe was the issue, then I would think pressure would have fallen off the table when you opened a faucet. If your house is holding 50# of pressure when water is being used, then it would appear that your 3/4" main line is supplying plenty of water. Could be wrong.

You stated that this was a problem on the SECOND floor. Is it a problem on the first floor? Is the problem isolated in the one bathroom with the tub/shower?

tjfiles1975 · Jan 20, 2011, 07:35 PM

The down stairs is tolerable. It doesn't have great pressure but will at least rinse water out of your hair. The upstairs however has to have a military style shower head to even be usable.

tjfiles1975 · Jan 20, 2011, 07:41 PM

It would actually drop close to 10psi with a couple of faucets own.

jlisenbe · Jan 21, 2011, 09:44 AM

I would think a 10 psi drop with two faucets running is normal. You lose about 4 or 5# of pressure going up 10 feet to a second floor, so that would not seem to be big. I just don't know.

Milo only has about a thousand times more experience that I have with this, so I would tend to go with his advice. At least putting in 350' of 2" plastic line won't put you into having to borrow money from the Chinese!

jlisenbe · Jan 21, 2011, 09:57 AM

I would think a 10 psi drop with two faucets running is normal. You lose about 4 or 5# of pressure going up 10 feet to a second floor, so that would not seem to be big. I just don't know.

Milo only has about a thousand times more experience that I have with this, so I would tend to go with his advice. At least putting in 350' of 2" plastic line won't put you into having to borrow money from the Chinese!