Hey there. Thanks in advance for your help. We have been having a water pressure problem in the house after we flush the toilet. The water in the bathroom and kitchen sinks and shower practically stop after we flush. The same thing happens if my wife uses the garden house in the backyard—there is no water pressure in the kitchen sink, barely dripping out. Would love your opinion to see if this is an easy fix or something major. I attached a short video to show you the water pressure difference when we use something else in the house or garden. Thanks.
No Water Pressure in House after Flushing Toilet or Using Garden Hose
- Thread starter richamooi
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Are you on a well or city water?
If you are on city water, do you have a PRV, Pressure Regulating Valve, on your incoming line?
It would be helpful to get a pressure gauge and monitor the pressure with no water use, with just a faucet being used, when a hose is being used, and when a toilet is being flushed. You can get a pressure gauge and an adapter to screw it one a hose connection at most any big box stores or on Amazon. If you have a washing machine hookup, you can use that connection. If not, and you only have the one hose connection in the backyard, use it and monitor the pressure when you flush a toilet.
Let us know what you find out, and we'll see what we can do to help you.
If you are on city water, do you have a PRV, Pressure Regulating Valve, on your incoming line?
It would be helpful to get a pressure gauge and monitor the pressure with no water use, with just a faucet being used, when a hose is being used, and when a toilet is being flushed. You can get a pressure gauge and an adapter to screw it one a hose connection at most any big box stores or on Amazon. If you have a washing machine hookup, you can use that connection. If not, and you only have the one hose connection in the backyard, use it and monitor the pressure when you flush a toilet.
Let us know what you find out, and we'll see what we can do to help you.
Thanks so much for your help. Yup, on city water. Let me track down a pressure gauge and will report back soon. Thanks!
There is a restriction somewhere. check your main shutoff at the meter and the service entry.
pasadena_commut
Well-Known Member
I think so too, and perhaps he can figure out where to some extent?
Thought experiment. Imagine 20' of pipe with a valve on one end and a restriction consisting of a pin hole on the other end, where the water comes in. At equilibrium the pressure on both sides of the pipe will be the same. When the valve is opened that 20' of water will come out, quickly at first, and then quickly taper off. If the valve is left open it will reach a different equilibrium, where the rate at which water comes out is just the flow rate for 80 PSI (or whatever the pressure is in the house) through the small orifice.
Now imagine that 20' pipe has a tee in it with another valve. Attach the water pressure meter there and open the valve. It will come up to house pressure. Open the other valve and the water pressure will fall to zero very quickly. (For some meters a reset button might need to be pushed to get a new measurement.) This suggests a way to find the restriction. Start at the hose bib were the water enters the house. If the pressure there doesn't vary (as in collapse) when a toilet is flushed then the restriction is inside the house, that is, downstream of the valve. If it does vary then it is upstream of that valve.
If the OP knows where all the pipes run in the house, and buys an adapter for the pressure meter so that it can go on a sink, or on a shutoff valve for a faucet or toilet, they should be able to determine roughly where the restriction is.
Is this house old with galvanized pipes? Does the OP find the aerators jamming up with tiny rust particles? This sort of restriction can happen when the pipes build up rust all the way across, or probably more commonly, when loose rust builds up into a sort of dam, with water only slowly filtering through. This can happen suddenly if somebody has been pounding on the old pipes, like to unscrew a stuck fitting. (Guess how I know...) If this is the case, and the problem is inside the house somewhere, it might be possible to clear the restriction (probably temporarily) by back flushing the pipe from downstream of the restriction. In the simplest implementation of this turn off the water at the curb, screw off the hose bib near the inlet (else it will probably jam with rust at its valve, or remove the valve from the bib), and run a hose from the neighbor's house to the bib the wife used to trigger the problem. (Flush that hose thoroughly before attaching it between the houses.) Turn on the water at the neighbor' hose bib, slowly. If the blockage is just a pile of rust it should be displaced and flow out where the hose bib was. If it is a lot of rust the water may need to be pulsed a bit to get it moving, and some wire may be needed to clear rust out of the pipe right at the exit.
If that works I would suggest then flushing it in the other direction. Remove the hose and either the valve or the whole bib on that end. Put the front bib back on or back together. Turn on the water at the curb. If the problem is solved some rust may come out, but the water should keep running out the back hose bib unimpeded. It is possible that the OP may need to go back and forth like that several times to work all the rust out of the pipe.
If ancient galvanized is the problem, repiping will be the ultimate solution.
Best thing to do is try that gauge on your silcock you can see the pressure at rest and then have someone use a fixture RS mentioned the strainer that's at the meter
It's almost certainly the PRV.
You have two pressures to measure: 1) static, with everything turned off, what is the number? This is the city pressure coming in. 2) Turn on something. What happens to the pressure? Assuming #1 was something like 80 psi, if the pressure drops radically, it is a restriction and it's 99% certain your PRV.
You have two pressures to measure: 1) static, with everything turned off, what is the number? This is the city pressure coming in. 2) Turn on something. What happens to the pressure? Assuming #1 was something like 80 psi, if the pressure drops radically, it is a restriction and it's 99% certain your PRV.
pasadena_commut
Well-Known Member
If there is a PRV.
Houses in my area were not built with those. City water pressure used to be lower, 65-ish if memory serves, but maybe a decade ago the city did something to its water distribution system and now it is 80 PSI where it enters the house. I don't recall any of the nearby houses having plumbing issues inside as a result of the extra pressure, but ironically, it broke many of the city's meters, which started leaking enough to fill and even overflow the box. Correlation isn't causality, but before the pressure increase I never saw leaking curb boxes, and after they were very common. To be fair, it is possible that they all hit 60 years or so and just failed from old age, for instance, some O-ring or gasket rotting out.
Touche' As soon as I walked away from the keyboard I realized the OP never indicated how old the house is.
foplumbing
Member
when did this start?
This may be hard to determine without looking inside walls, but is that kitchen much farther away from the w/c or garden hose in relation to the main shutoff?
This may be hard to determine without looking inside walls, but is that kitchen much farther away from the w/c or garden hose in relation to the main shutoff?
Sorry for the delay to the answers, but I was out of town and could not check the water pressure. We get water from the city, and from what I can tell, there is a PRV where the water comes in to the house behind the washer in the garage. I tested the water pressure in the backyard, from the main faucet we use for gardening with the hose and it is 40 PSI without anything else running in the house.
What's the pressure with at the hose connection with just a faucet being used and what is it when a toilet is flushed? 40 PSI is on the low side to begin with, so your PRV may have mineral deposits keeping it from working properly. After checking the pressures with the fixtures running above, you may want to try to adjust the PRV to a higher setting. But that still may not work if has mineral deposits in it and/or it has a filter that is plugged.
Thank you. When I run a second faucet, that backyard faucet drops to 20 PSI.
Yes, you have a problem that is likely caused by the PRV. As I said, you can try to adjust it, but I'm betting it is partially plugged or the internals are frozen with mineral buildup. Post a picture so we can determine what brand it is.
