FAQs about how to fix poor water pressure traced to clogs, pipe diameter, or clogged water supply piping.

This article series describes How to Cure Bad Water Pressure Due to Clogged Water Supply Pipes. The process of diagnosis and the costs of the repair are explained.

Clogged Water Supply Piping / Poor Water Pressure & Flow Repair FAQs

These questions and answers about improving poor water pressure or flow traced to clogged piping were posted originally at CLOGGED SUPPLY PIPES, REPAIR - be sure to review that article.

Sketches courtesy of Carson Dunlop Associates, a Toronto home inspection, education, & reporting tool firm.

When a water supply pipe pressure has been traced to supply pipe clogging there are several repair approaches that we can try.

But it makes sense to try for a correct diagnosis of the problem before spending on wild guess repairs.

[Click to enlarge any image]

Comments:

(Dec 2, 2012) Gary Los Angeles said:

Thank you so much for your wonderful excellent helpful website reviewing and educating about these difficult plumbing problems!

Reply:

Gary,
Thank you so much for the nice note. We work hard to provide accurate, unbiasd information, so are of course thrilled when a reader finds our website helpful. Questions or critique help us too.
- Ed

Question: bad water pressure at just some fixtures

(Apr 15, 2012) Tony DAteno said:

My problem is I had good water pressure in bathroom sink, but not in shower or kicthen sink, hot and cold are fine in bathroom sink the other 2 are not. I have well water .

Reply:

Tony, take a look at the bad water pressure diagnostic suggestions in

• WATER PRESSURE PROBLEM DIAGNOSIS TABLE

You're on the right track - if some areas have good pressure and flow and others not, I don't tend to suspect a system problem. Look for clogged strainers first, then clogged or shut valves, pipe elbows, piping.

Question: oscillating water pressure on high iron content water system

(Apr 29, 2012) Roger Hogarth said:

I have a private well with high iron content. The water pressure fluctuates enough that my in-ground sprinklers will stop oscillating when the pressure drops and then start again when the water pressure resumes. This pressure fluctuation is also noticeable in the shower and at all faucet heads. Can you give me any ideas on what to do?

Reply:

Flush out lines, acid wash piping, install an iron removal system are the rather obvious fixes that occur, but I'm unclear on why iron content or pipe clogging would cause pressure fluctuation except for one most likely cause: the pressure control switch mounting tube, water pressure sensing tube, or switch pressure sensing port is debris clogged. Try replacing those parts.

Question: need to acid wash water pipes to remove scale to fix clogged water supply lines

(June 12, 2012) donna chavers said:

i have calcium built up in my cold water pipes & was told to use vinegar but how do i flush it through my pipes

(Mar 17, 2014) mack lovelace said:

My sisters cold water supply is blocked. Is the anything I can do to keep from having it replaced. I have checked all the strainers, valves etc. Also replaced the jet pump and pressure tank so it must be blocked The water works fine from the faucet just past the pressure tank but not in the house. We can't really afford to have the lines replaced

Reply:

Donna,

a plumber can try an acid flush on your piping system - don't try it yourself as it's dangerous and also requires a pump that is not eaten up by the acid. Beware that there is a risk of pipe leaks.

Mack,

Mack, from just the information in your note we can infer that the problem is not the well, pump or tank, since you have water flow past those. So you are looking for a blockage between the point where you have good water flow and the rest of the building.

If the blockage occurred suddenly I'd look for a closed or damaged shutoff valve or less likely, an obstruction at a pipe elbow or bend.

I don't assume that extensive piping replacement is necessary. More likely a series of tests beginning by examining piping between the working faucet and the next closest fixture that is not getting water, is the process to follow.

If the blockage is not total but water flow is slow at fixtures, don't forget to test by removing strainers at faucets and shower heads.

Question: weak water pressure after changed pump pressure control switch

(Aug 4, 2012) Angel said:

I changed the pressure switch to the water pressure tank and now I've been with 30 persent pressure. I did replace the switch with a 30 / 50. Why no strong water pressure? help

Reply:

Angel if your new pressure switch was set to on at 30 psi and off at 50 psi, and if the pump starts, runs a while, and reaches that 50 psi cutoff and stops, then your pressure tank is sitting at close to 50 psi.

But if you have poor water quantity flow at faucets (which people call poor "pressure") at one or all fixtures, pipes or fixtures or even just a faucet strainer could be clogged, as we discuss above.

Having higher water pressure doesn't help fix that problem very much since you are trying to force water through a small opening. Think of it as 50 psi through a 1-inch pipe versus 5o psi water forced through the eye of a needle. The second case is going to give you very little water flow.

Question: Trouble with Sloan Royal Flushometers in women's restroom

(May 31, 2012) Ryan Beaudoin said:

So this might be a tough one to answer and ANY help is appreciated.

At my work, in the women's restroom we have two individual stalls with 1.6gpf closets. On those we are using Sloan Royal Flushometers.

About a year ago I replaced the entire sloan valve on toilet #1 because of slow flushing. After replacing the valve with no success, I replaced the toilet and smashed the old and found a piece of plastic in the trap, which could not be "snagged" by the auger.

After replacing the toilet everything went back to working as normal. Just last week we started experience the same problem. This time i pulled out the relief stem on toilet #1 and let the toilet go into a constant flush.

The water drained fine and there was no buildup. Toilet #2 (which shared the same supply) when relief stem was pulled it also went into a constant flush.

Again the water drained fine, but it appeared that there was a bit more water pressure in toilet #2. Do you think I could have a partial clog in the supply line on toilet #1? Note: I replaced diaphragm on toilet one and removed the flow ring on it.

It seemed to improve the flush power. Im thinking my next step would be to test the supply pressure and/or replace the toilet. Any suggestions?

Reply:

Ryan, I'd think that you wouldn't have to replace the whole toilet, just pull it from its mount and inspect the entire flush route for blockage.

About water pressure, when two fixtures are quite close together and one seems to have lower pressure, while I don't rule out a water supply pipe problem (such as a big solder blob during supply line installation of the slower fixture), there can also be a problem in the flusometer itself.

Question: strong water pressure then suddenly drops very low very quickly

(Jan 28, 2013) wayne said:

water presure good then drops fast

Reply:

Wayne it sounds as if your building is on a private well & pump and that the pump is not coming on when it should AND the water pressure tank may be waterlogged.

Question: water softener resin tank exploded - now pipes are clogged with resin

(Mar 2, 2013) Bert said:

I had a water softener resin tank explode and dump black resin rocks into my hot and cold water lines.

It plugged every "at faucet aerator" . When I remove these, there is so much resin in the line, that I have no hot water and a bit of cold at various outlets. I have bypassed the softening system (built in valves). How can I 'rinse' all this stuff from my lines?
Thanks,
Bert

Reply:

Bert you'll need to remove all faucet strainers & shower heads to flush out the system; if that's not enough you may need to disassemble some of the water shutoff valves.

Question: Shuddering cold water line

x(May 8, 2014) pink said:

my cold water tap and toilet make a shuddering noise just few months knw and none of the other units have this problem only me why can u help plse .
kind regards
pink

Reply: water hammer troubles

Pink I think you're describing a water hammer problem - please see

inspectapedia.com/plumbing/Water_Hammer_Noise.php

Question: leak between water meter & supply pipe under a slab

(June 3, 2014) Connie Jones said:

There is a water leak between the water meter leading to the house and the supply pipe immediately under the slab leading to the kitchen sink. The water meter was replaced by the city because the bottom of it had rotted. However the leak continues.

When the water is turnded on from the street, the water leaks under the slab in front of the kitchen and in the yard in front of the kitchen. However it does not leak inside of the house.. What specific pieces of the water supply pipeline should be checked by a plumber? What are so possible causes of this problem?

Reply:

Connie, it sounds as if the plumber will need to either excavate or drill below the slab to replace leaky supply piping or it may be less costly to abandon that supply and install new piping by another route.

Question: poor water pressure, clogging of water system after a water main break

(June 23, 2014) Kyle said:

Had a water main break over the winter. It was recently fully repaired.

My water pressure has dropped off significantly. I have removed all strainers from faucets and cleaned out all debris.

Suddenly we have very little water very little water pressure today. I suspect that there is debris in the line between the the water main and the house. What can be done to diagnose and/or repair?

Reply: check for a debris clogged water pressure regulator

Kyle, a likely clog spot could be at the house water pressure regulator.

Question: water pressure trouble after meter changed

(June 27, 2014) John said:

Water Board changed my meter outside flat, dropped card through door..

Never ever had any pressure or blocking problem before, been here years.

Pressure dropped immediately, to drizzle, had to call them out. They eventually found a small piece/lump of concrete inside pipe to kitchen which caused blockage. Is it possible when an operator is changing a meter outside, for debris/pebbles/gravel etc to get in?

Reply:

Yes, John.

Question: how to clear silt out of water supply pipes

(July 6, 2014) how to clear water supply pipes clogged with silt said:

My well water was full of silt/clay. The water is clearing up. However, I cannot get any water from some of the faucets. I think the silt/clay is clogging the pipes. How do I clear the water pipe? Thanks Joe

Reply:

Joe

Start by unscrewing the filter/strainer at each faucet, run water full-speed to flush the line; clean the strainers before reinstalling them.

Question: poor hot water pressure & flow from tankless instant LPG water heater

JAC said:

We have an old tankless Instant LPG water heater. It has worked perfectly till recently. Turn on the hot water it runs fine.

Turn on the cold water to mix and the temperature fluctuates from hot to cold. Cannot have a shower. Have now adjusted the hot water such that we only use the hot water and not the cold.

This problem does not occur in the kitchen or the bathroom sink only the shower. The shower head is new. HELP!

Reply:

JAC

Tankless heaters, most of them anyway, include a safety feature that will shut down the heater if the water flow rate through the heater is too slow - avoiding overheating and damage or unsafe conditions. When you turn on the cold water pressure you are reducing the overall house water pressure at the tankless heater inlet.

That small pressure drop combined with possibly slower flow due to mineral scale deposits in the heater itself may explain the change in your tankless heater performance.

If you can find an experienced installer who knows your system it may be possible to clean or de-scale the unit, restoring its full function.

See these hot water pressure diagnosis & repair articles

HOT WATER PRESSURE IMPROVEMENT

TANKLESS WATER HEATER REPAIR GUIDE

Question: is acid flushing of water piping somethiing a homeowner can do herself

(Sept 26, 2014) isa frongia said:
thankyou for all this info however after still researching on the Inspectapedia, what is the answer to the following question:

Is "acid flushing" for low water flow in a home doable on my own and how to do it?

I have this problem for all fawcets and we believe it is mineral buildup.
Please help on this one.

Reply:

Isa

I don't recommend do-it-yourself acid flusing of water pipes. An experienced plumber will get the job done faster, safer, and probably at lower cost than you can because she will

1. Already own an acid-resistant pony pump needed to circulate acid solution through the water piping system or coil or heater
2. Know how to find or install the necessary plumbing fittings to connect the pump and acid solution to the piping system
3. Have the acid, connecting pipes, and plumbing parts to install fittings right on the truck
4. Have experience dealing with acid

Question: dirty water from municipal supplier - how can we improve it.

(Sept 27, 2014) ARUN MISHRA said:
The water supply which we receive from muncipal corporation is very dirty due to some supply problems. We cannot even use it for domestic purposes such as bathing washing etc. Is there any method to improve the water standard by use of any external kit for the whole bulding.

Reply:

Arun, I would

1. Discuss this issue with your municipal water supplier, as in most jurisdictions federal clean drinking water regulations require that the drinking water be safe and usable in community water supplies. Of course depending on where you live that may not be the case. So continuing, I woul d
2. Have the water tested to identify the contaminants.
3. Install a suitable water filter or treatment system depending on what is in the water supply

Question: r pump was running full time and not turning off, now weak pressure

(Sept 30, 2014) Jenn said:
Hello! Wondering if you can help with our water problem. About a week ago we noticed that our pump was running full time and not turning off. We took the pump off the line and took it in for repair.

They made a quick (and cheap - $45) repair and told us it was good to go. (We're still not sure what they fixed.) We put the pump back on and still the pump would not shut off. We finally got a pressure gage and discovered that the pressure at the pump was only 10psi.

Today we pulled up the intake pipe and replaced the foot valve, hoping that would solve the problem.

It's got the pressure up to 15psi, but still not enough pressure to shut the pump off. We have added air to the pressure tank, primed the pump every time we've disconnected it, put a new pump switch electrical box on the pump, and still nothing. We can turn the pump on enough to get some water in the house, but the pressure is poor, and the toilet tank won't fill....and the pump still runs.

Our well is fairly shallow (the foot valve is about 25' below ground) but we can see water in the well casing. We are at the bottom of a valley next to a river bed and we are pretty sure the water supply is not the problem, but are inclined to try a new pump, or take the old one in again.

Any advice you can offer would be helpful...we're at our wits end!

Reply:

Jenn

the diagnostics at

WATER PUMP WONT STOP RUNNING

should help you find and fix the trouble. Let me know if you need more help.

Question: iron clogging the water supply system

Oct 10, 2014) goltu jain said:
my water supply line has block by water iron so how to clean the same as our innerline fitting in building

Reply:

x

Question: lower water pressure after municipal supplier changed the water meter

(Oct 31, 2014) Anonymous said:
Two years ago the water district came out and changed the meter at the curb. After that I noticed my water pressure decreased. Over time, I can only use one faucet at time. I cannot take a shower with the washing machine running at the same time.

The digital indicator flashes "no water" and the washing machine starts beeping. The water pressure in the entire home is extremely low. I notified the water district of the problem, and they came out to test the water pressure. Of course the pressure was fine from the street.

The water district advised the problem was on the property. I have the turned the water valve as far a I can to get the most water possible. Ignoring the problem is not making it better. Any suggestions?

Reply:

Anon:

Possibly the repair resulted in a blockage due to improper soldering or release of debris into the water system.

Pressure and flow are NOT the same thing at all. Measuring pressure alone won't diagnose this problem and is misleading.

Measure the flow rate at a faucet closest to the incoming water main.

Question: Have low cold water pressure at my sinks.

(Nov 11, 2014) EM said:
Have low cold water pressure at my sinks. System is residential well with water tank installed 1981 and has a gauge pressure of 30 psi and a 28 psi at the top valve? With no filter at sink hot water runs steady flow and clod is slower running?

What may be the problem? Is it the old water tank that needs replaced or another issue?

Question: relationship between pipe diameter and water pressure & flow rate

(Apr 30, 2015) Robin Layton said:
it appears as if your illustrated formula for finding area of a pipe is incorrect.

although your answer is correct the formula isn't. area of a circle is pix r squared. not pi times r as you have listed. I understand this as you are plumbers after all. but misleading

Reply:

Thank you so much, Robin, I'll correct the text above. I don't know how our exponent on the radius r got lost in the illustration but I've contacted Al Carson who informs me we were using an obsolete sketch.

Al provided and we have inserted updated illustrations. Cason Dunlop Associates, a Toronto home inspection and education company have graciously shared technical information and illustrations with InspectApedia.com

We appreciate your careful eye and editing and more, taking the time to write.

Question: no watger pressure after replacing broken pipe

1 June 2015 gene said:
i replaced a broken section of pipe but now i have no water pressure tho the pump is pressrized where iyt needs to b and i can hear water in the pipes at the main to the house?

Reply:

Gene

I'd look for a solder or debris-blocked pipe or elbow or sink strainer screen or pressure regulator inlet, or for a valve someone forgot to open.

...

Continue reading  at CLOGGED SUPPLY PIPES, DIAGNOSIS - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see more-recent CLOGGED SUPPLY PIPES, REPAIR FAQs-2

Or see

PEX BRASS CONNECTOR LEAKS where we discuss corrosion build-up in brass elbows & tees that can clog PEX piping systems.

WATER PRESSURE BOOSTER PUMP

WATER QUANTITY IMPROVEMENT - steps to increase well yield or other means to improve water flow into the well itself

Suggested citation for this web page

CLOGGED SUPPLY PIPES, REPAIR FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Questions & answers or comments about how to de-clog or de-scale building water piping.

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Citations & References

In addition to any citations in the article above, a full list is available on request.

---

ADVERTISEMENT

---