Where is the water pressure problem coming from?

Discussion in 'Pumps and Tanks Well Forum & Blog' started by buenasuerte, Jun 18, 2008.

  1. buenasuerte

    buenasuerte New Member

    Messages:
    2
    Ok....this is a long explanation, please bear with me:
    We are on an old gravity-fed system (well and large above ground holding tank)that is shared by 4 households on one rural road. The line drops in elevation from the tank across the street and then supplies the houses first from the lowest elevation and then on up the road, with a slight elevation gain as the line progresses. We are third in line in this system and none of us has had terrific water pressure for as long as we have lived here. Most of us have grown used to this and have been fine with it, but one neighbor, the last in line, now uses the house as a rental and, understandably, wants increased pressure for the renters. The owner prior to the current one was actually the one to install the pressurization system as a matter of "improving" it for resale. After installing some sort of pressurization method (I have no idea what), our water pressure was instantly reduced a good part of the time to nearly zero (they watered their lawn almost constantly the first couple months). After making the neighbor aware of the situation, and following the advice of plumber friend that he should have had a "holding tank" installed, he listened, did a bit of research and we were told that he was going to install a tank of some sort. I have read up on pressure tanks since then, but at the time, I knew nothing about how pressurization worked, so my explanation here of exactly what was installed probably won't make much sense, but my understanding was that initially he was somehow drawing water directly into his house and pressurizing it....I don't know how.... and only later did he learn that a tank, or maybe it was simply a larger tank?, should have been installed, which, whatever change he made, it worked, and our water pressure improved right away.

    Ok, so he sold the house several years back and another owner is in the picture. Our water pressure is the same as it has always been....usually, but occasionally...and with more and more frequency over the last year or so, our water pressure will cut out for around 45 seconds at a time, both hot and cold....first to almost nothing and then to maybe half our normal pressure. It seems to be getting worse over the last several months. One time we had the neighbor on the phone and asked if the pressure tank was kicking on right then and it coincided exactly with our drop in water pressure.

    So...since this neighbor rents the home out as a vacation rental in the summer there is a great motivation to have the best water pressure possible. I understand that. We have asked repeatedly for the owner to get the system checked because it still appears to us to be what is negatively impacting our water pressure. We still don't mind the "normal" lower pressure that we have always had, but the cutting out is getting quite annoying...especially when showering.....brrrr. The owner claims to have received assurance from several people that it could not be the system that is causing our problems. Our pressure drops seem to happen almost always when someone is home next door. When no one is there for several days, there is usually no drop in pressure, although this has happened on occasion, and the owner mentioned recently that they had a small leak somewhere. The coincidence explanation seems a bit unlikely to me, but...I could be convinced otherwise if someone who really knows about such things has a better explanation. Our pressure is consistent except for these 45 second intervals that occur at various times through the day.

    Does anyone have any idea if it really could be the neighbor's system which is causing a drop in our pressure? And if so, is there a simple way to determine where the problem is? If not, what could the problem be in our own system since we are completely gravity fed and have no pumps or electricity (other than hot water heaters) involved? We have a large house and have experienced the same pattern of a drop in pressure (severe drop, followed by about half pressure for about 45 seconds, then back to "normal" pressure) from many different spigots/faucets/showerheads. Finally, if this IS the neighbor's issue and they will not address it, if WE install our own pressure tank, will this restore consistant water pressure for us?

    Thank you so much for taking the time to read this and for any thoughts you might have.
  2. leejosepho

    leejosepho DIY scratch-pad engineer

    When you say "gravity-fed" system, are you talking about a water tower? Also, who is responsible for maintaining the common system?

    In any case, whatever pressure is at the source can only push a certain amount of water through the main line (of whatever size) to the four houses, and some kind of booster system at any house surely could take water away from the others.
  3. valveman

    valveman Moderator Staff Member

    Messages:
    4,382
    Location:
    Lubbock, Texas
    The booster pump at the neighbors house will basically "suck" the pressure out of the main line. I can't believe they are not getting air in their system when you have NO water and a tap is left open. If everybody puts in a booster pump, you will suck the line dry. Everybody needs to put in a storage tank with a float valve. Then use a booster pump and pressure tank to draw water from the storage tank.

    Or you could put in a single larger booster pump and pressure tank at the base of the water tower, to feed all the houses.
  4. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    If someone is taking water off the line using a booster pump it can easily drop the water pressure in the line. It could even drop the pressure below atmospheric pressure which is a safety/health hazard because a leak could allow contraminated ground-water to enter the distribution pipe.

    Four houses on a line might make the system fall under rules for a public water supply, subject to state utility and safety rules.

    The problem could be caused by someone at the end of the line adding a larger or more effective pump.

    If you are satisfied with the pressure that you get you could add a bladder tank to your system without a pump. You would need a check valve in the line coming into your house, before it gets to the bladder tank or your water pipes.

    The bladder tank should be precharged with air to the minimum pressure that provides satisfactory service for you, and somewhat below the maximum pressure delivered by the supply line. A modest size tank would get you past the brief periods when the neighbor is pumping water.

    If you tell us what is the maximum pressure in the line, and the minimum pressure that is satisfactory to you, I can calculate how much water you would store with various size bladder tanks.

    If a tank alone doesn't provide a satisfactory solution then you can add a small pump of your own. It should be the smallest pump that will provide adequate flow for your needs.

    If you want to put in the pump immediately you can use a smaller tank so the total cost of pump and tank would be less if you do the whole thing at one time. The pressure switch could be set so that the pump runs only when the pressure drops lower than satisfactory for your needs.

    It will almost certainly make the problem worse for your next downhill neighbor.
  5. buenasuerte

    buenasuerte New Member

    Messages:
    2
    Thank you!

    Thank you to all three of you for taking the time to listen and respond. I appreciate it very much! You have answered the first big question about where the pressure drop is coming from and that is a huge thing.

    I forgot to mention one thing in the first post and that was that our neighbor describes their "normal" pressure as "unlivable", saying it takes a half hour for the toilet tank to refill when their pressure system is turned off. Their house is probably only 75 feet away from ours and nearly the same elevation and so it seems to me that our pressure ought to be fairly similar. Our normal pressure doesn't drop within our own house even with multiple taps open or the toilet flushing and our toilet tanks fill pretty quickly, I think. Prior owners next door have never complained of low pressure like that so something has happened recently. In the past, we have experienced sediment or buildup in our own faucet screens and showerheads which affected pressure at that particular location. When we cleaned or replaced each, the pressure improved there considerably. Is it possible that some sort of buildup could be playing into the situation next door? We have asked our neighbor what components are presently in their system and how it is configured in hopes of better understanding what the setup is over there and hopefully to help figure out what the problem is. They are looking into it as they weren't sure, but their description sounded like a tank and a pump of some sort. Whether there is a pressure tank and if so, what kind, is one thing I don't know yet.

    As for our own system, I am going to do some more research on the various elements you have all mentioned or suggested (tanks, pumps, valves) so I can at least ask semi-intelligent questions of you. We really have been fine with the pressure at the house as it has been, so it would be great if our neighbor resolves their issue, whatever it may be, and we can just go on without installing anything new for now. However, I have to say, it is a big relief to know that there IS something we can do on our own that will remedy the situation for us should nothing new be done next door. Whatever we do, we don't want to impact our downhill neighbors negatively. So....I have some learning to do on some basic terms and concepts (as well as pressure minimum and maximum values for our system) and then I'll likely be back to ask for more advice.


    Thank you again so much!
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