Pressure tank after softener? (city water)

[fergus121]

My water comes from a rural water supply company (effectively it's city water; I don't have a well). The static pressure is 60 psi, but there's about 400 feet of 1 inch PVC pipe between the water meter and my house. As a result, I experience noticeable (dynamic?) pressure loss when more than one tap is open. For example, the shower pressure is poor if someone is filling a bathtub or using an outdoor faucet. I'd like to install a water softener, but I'm afraid it would make the water pressure in the house even worse.

Does this sound like a workable solution: water supply pipe -> softener -> check valve -> pressure tank -> house?

I'm thinking about it like the pressure tank on a reverse osmosis system, but on a much larger scale. My thought is that when demand exceeds the supply coming from the pipe for a short period, water from the pressure tank (at the house) will make up the difference and maintain the water pressure. It seems like this would be more effective after the softener, because water from the tank wouldn't be subject to the pressure loss from the softener.

Do you think this would work in practice? Am I overlooking something?

Thanks very much for your input!

 

[Reach4]

A pressure tank only holds about 25% of the nominal size of the tank of water. Given that limitation, your idea would work. I don't think the effect will be quite what you want. I think you may want to drop the water pressure to zero on some schedule, so the water in the tank gets replaced. I don't know what that interval would be.

A water softener only consumes water during regeneration, and you select the time for that to start. The default is 2 AM, and regeneration lasts roughly 1.5 hour. Most of the cycle is not drawing water at the max amount. The softener will usually regenerate after 7 days or more. So it will not be competing with the other uses. A 1.5 cubic ft 10 inch diameter tank , usually uses 2.4 GPM and a 12 inch diameter tank uses 3.5 GPM. That is small compared to a bathtub filling. Yes, it is possible that you will flush a toilet during regeneration, and the refill could slow a bit.

Some people use booster pumps to increase pressure. That is an item that can fail, but it may be worthwhile to you.

I don't know what it would cost to get your water line replaced with 1.5 inch polyethylene pipe, but that would roughly cut the pressure drop over the 400 ft to about half.

Get a pressure gauge. Measure what the drop is now. You can get a gauge with a garden hose thread. That can go on a laundry tap, outside spigot, or on the drain for the water heater.

 

[Sponsor]

 

[Bannerman]

Suggest checking your main shutoff valve to ensure there isn't something broken or jammed inside which maybe restricting flow. You may want to replace that valve with a full bore ball valve if your main valve currently is a gate or globe type.

As it is a shared water service with other homes, there could also be a back-flow prevention device located near to the main valve. The back flow device should also be checked and rebuilt if necessary.

As the water is supplied by an outside company or municipality, there is typically a valve located near the boundary of each property for the water company to shut-off service to each. You may want to contact the water company to describe your situation and ask them to test their service valve and meter to ensure neither is the source of restriction.

 

[Mikey]

Over 400', the pressure loss at 10gpm in 1" PVC is only a little over 10psi, so I think Bannerman's on the right track. I had a similar problem when I moved into my current house. In my case, the main shutoff in the house was an ancient gate valve that was hard to turn, and the previous owner only turned it a couple turns. All the symptoms you have, fixed by opening the valve. Same thing in the hot water -- the valve at the WH was a gate, opened only a turn and a half. The temperature in the pressure-balanced showers fluctuated wildly with changes in cold water demand.

 

[Mialynette2003]

A pressure tank will only be a storage tank in your application. You would have to add a booster pump to boost the pressure.

 

[fergus121]

Thanks for the advice. I'll check the line again for any restrictions, but I'm almost certain there's just a ball valve at the water meter and one at the house and they both seem to be in good shape (turn easily).

Regarding the original idea- I was thinking that the pressure in the house would be roughly the average of the pressure in the tank and the pressure of the water coming in through the pipe. So assuming the tank was charged to 60 psi (static pressure of water supply) and the dynamic pressure of the incoming water was 45 psi (after going through 400 feet of pipe and the water softener), I'd see something in the mid-50s inside.

But now I think that's wrong because of the check valve. The first water would come from the tank, then when the tank pressure dropped enough to open the check valve, the rest of the water would come from the water supply pipe. So I'd see no real benefit.

It sounds the only solution is a bigger pipe like Reach4 said. But before I do that, I think I'll just add the water softener and see what happens.

Again, thanks for all the help.

 

[Bannerman]

While a 15 psi fluctuation would be noticeable, 45 psi remaining should be ample pressure for operating multiple fixtures. The 10 psi drop Mikey referenced, is when drawing 10 gpm, which is considerable and more than an average household would use at one time.

Even if the current service and main valves are ball types, that does not necessarily signify they are 'Full Bore'. Full bore valves incorporate a straight through water passage that is as large as the pipe ID whereas common ball valves utilize a much smaller water passage diameter. While it could be assumed a 1" main line would utilize a full bore valve, nothing should be assumed. Perhaps the plumber ran short and installed what he had at the time. It maybe best to verify the valve model number(s) against manufacturer specifications.

As it seems you maybe able to access the service provider's valve at the meter located at the street, I suspect that is not the only valve controlling water service to your property.

Unless a softener is smaller than required or is regenerating when household water is being drawn, I would not anticipate a softener to cause a noticeable drop in water pressure during regular water use.

 

[ditttohead]

A softener or any additional plumbing for that matter will drop the pressure. To what degree is the real question. All of these are calculable but probably not worth the time in doing the math. For your application the idea of a pressurized tank would be helpful but as stated a simple booster pump may also be needed. A properly designed booster pump could correct the problem.

Totally agree with adding a pressure gauge to see what happens when the water is run... I have seen many applications where a tank/pump is installed only to find out the plumbing inside the house is the actual problem. 1/2" Pex run from one side of the house to the opposite side, then teed to deef a couple items always makes for terrible flow rates.