Low water pressure (booster pump advice)

[Andrew S. McKay]

Built new in 1995. Have water from community tower. All neighbors have very good pressure and flow. My house is much further back from the road than most – builder used 3/4″ pipe from the water main to my house (a 500′ run!). Low water pressure everywhere. 99% sure the long run of small ID pipe is cause for poor flow and pressure.

Finally sick and tired of this. At first, I thought I needed a holding tank and pump, but talking with a couple local plumbers, they suggested a booster pump set-up. The booster pump comes with some type of very small (5 gallon?) “holding tank”, so it does not shut on and off every single second.

Any recommendations? Links (USA only) as to where I could get a booster pump kit online?

-Mark
Maryland, USA

[kookParticipant]

Nobody has any info on this???

[Robert Stephen MortonParticipant]

Kook, what is the height of the tank?
If the height of the tank was 100ft high, then you would need a min of 1.1/4″ or 32mm poly over that distance to deliver a reasonable flow.
You said that you freeze at temperatures of 85deg. are you confused as flow has nothing to do with temperature. pressure will not be affected by the length of the delivery pipe.

[kookParticipant]

quote:

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Originally posted by Robert Stephen Morton:
Kook, what is the height of the tank?
If the height of the tank was 100ft high, then you would need a min of 1.1/4″ or 32mm poly over that distance to deliver a reasonable flow.
You said that you freeze at temperatures of 85deg. are you confused as flow has nothing to do with temperature. pressure will not be affected by the length of the delivery pipe.

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Height of the community tower? Dunno – gotta be 100′. What’s done is done, as far as the 3/4″ line to the house – no changing that – would cost thousands of dollars.

I’m sorry, I didn’t think I said anything about temperature – did I miss something?

You are telling me that the size of the pipe has nothing to do with pressure? I am having a hard time with that. It makes sense to me for static conditions, but while flowing water (say watering the yard, or starting a load of wash), the pressure has GOT to be significantly lower than it is out at the street, no?

[Phil_HParticipant]

Kook,

I can’t help you with locating a pump but I thought I would add some information which you might find useful. First, yes you do get pressure losses in water pipes due to friction loss. Different pipe materials etc vary but here are some examples for 500 feet of 3/4″ type K copper: 3.2psi loss @ 2.00gpm; 13.0psi loss @ 4.00gpm; 41.6psi loss @ 8.00gpm.

I think Robert was asking about the water tank elevation because he was thinking a larger supply pipe would be better than a pump. For a gravity system the elevation determines the maximum pressure available. Every 2.31 foot of elevation (head) equals one psi. If the tank was 100 ft higher than the main, you would have 43psi available there. If your house looks down on your neighbors, the elevation change would contribute to your inadequate water supply.

I would typically lean toward a larger pipe rather than a pump if that alone would be sufficient. But, It sounds like you have already talked to some plumbers, and I am guessing that you have a pretty good idea of what a new pipe would cost compared to a pump.

One more thing to consider is the flow velocity if you keep the 3/4″ pipe. As the velocity increase, erosion of the pipe increases and the effects of water hammer increases. Building codes, manufactures, etc. state different maximum velocities. 8(plastic)-10(metal) feet per second are typical maximums recommended for residential cold water. That is about 13-16 gpm for 3/4″ sch 40 pipe.

Hope this was useful
Phil H

[fourth yearParticipant]

If volume is adequate but pressure is low due to low static pressure then a booster pump will help. In your case the static pressure is okay, but the dynamic pressure is inadequate due to the long service line. In this case the pump would probably be “starved” for water while it was operating, causing pump cavitation and severe damage to its operating parts.

[kookParticipant]

OK then – what’s a poor boy to do? I will not spend the $2k+ to get a larger line put in. Some type of holding tank set-up with a pump placed after the tank? The one case where I can see something like this not working effectively is watering the yard, were you have a continuous, long duration flow of water – the holding tank will get drained within 10-15 minutes – may get nice flow for that first 10-15 minutes, but after that, same old problem.

[fourth yearParticipant]

We had a whole subdivision here that had to do just that. Mopst of them were about 600 gallon tanks. The tank was filled with a float valve and then the pump drew from that. You would need a low water level switch to turn off the pump when the water supply was deleted, and an override so it would not come back on until there was sufficient water restored in the tank.

[kookParticipant]

600 gallon tank for each house???!!! There’s no way I can consider that. Seems the cost would be more than installing a larger line. Can you elaborate?

[fourth yearParticipant]

The tank is not extremely expensive since it is not a pressure vessel. You can now get plastic tanks that for a very reasonable amount. Then you need a conventional shallow well pump system with its own tank, probably 50 gallons. Space might be more of a consideration than price. You could possibly do the whole thing for about $1,000.00 to $1,500.00, depending on the prices in your area.

[Robert Stephen MortonParticipant]

If you install a booster pump, you will increase the frictional losses to a stage there will be no water to pump! Cavitation will enter the picture! your pipe sizing is too small, If you start out wrong, corrective measures demand going back to the start & resize. Calculate the cost, you say $1000.00 against the pump cost + installation of power and the plumbing then add maintenance & running costs, the $1000.00 sounds cheap to me, and far more proffessional

[Robert Stephen MortonParticipant]

Kook, I am fro Australia. In Queensland Australia the Regulations require that any water service must be sized to give a minimum pressure at any outlet of 5mhead (aprox 5.5lb) with a max velocity of 3m (10ft) per second.
You have to weigh the costs of the supply & installation of a tank (break tank) the ongoing certification for backflow, the electrical connection, maintenance. as agains the upgrading of the 3/4″ service to an adequate supply, in Australia this work can only be done by a Licenced Plumber, licenced as a Plumbing Contractor and he would have to upgrade the service at his own cost if it failed to supply the required water at the required rates. Don’t your plumbers have any responsibility to supply water to the consumer at a given rate?

[kookParticipant]

LOL – my builder went bankrupt after building my place – I’m on my own here. I got a good house, built to my specs, at a decent price. However, there are a few items where he f*cked up – the water supply being the big one.

I haven’t researched it too much, but the cost of digging a new trench (thick woods) and installing new line would be at least a couple thousand dollars US.

[Author]

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