Hot water tank control valves Carson Dunlop Associates Hot Water Pressure Loss FAQs
Questions & answers diagnose hot water pressure

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Hot water supply troubleshooting FAQs:

Questions & answers on how to diagnose the cause and decide the cure for rapid or sudden loss of hot water pressure at plumbing fixtures in a building.

This article series explains how to diagnose the loss of hot water pressure, quantity, or flow in a building.

Green links show where you are. © Copyright 2017, All Rights Reserved.

FAQS on Loss of Hot Water Pressure & Flow in a Building

Sketch of a tankless coil tempering valve or anti scald valve (C)Carson Dunlop AssociatesBefore you start fixing or buying stuff to fix a hot water problem hot water problems and diagnostic guides for all kinds of hot water troubles are summarized at WATER HEATER PROBLEM DIAGNOSIS.

Shown at left, a tankless coil used for making hot water in a heating boiler, courtesy of Carson Dunlop Associates, a Toronto home inspection & education company. [Click to enlarge any image]

On 2017-03-06 14:53:16.968552 by (mod) kitchen faucet hot water slow after water heater replacement

If only that faucet, try removing the strainer and cleaning it at the faucet. Debris from soldering or making pipe connections can sometimes flow through to clog a faucet or a stop valve on the piping system.

On 2017-03-06 14:48:34.228700 by fred

just installed a new hot water tank, now the kitchen faucet has only a trickle of water
from hot or cold side. took filter screen off inlet of faucet but nothing wrong there. what should I look for from there.

On 2017-02-22 20:03:32.829773 by (mod)


A clog may have blocked hot water leaving the heater, such as debris from a deteriorated dip tube or lime-scale formation that broke off to form a chunk that blocks a pipe.

On 2017-02-21 16:21:19.670197 by (mod) no-hot water at some fixtures

How baffling. If there is hot water at the sink but not at the shower, and if the shower has good cold water pressure I can but think that the hot water valve or pipes to the shower are clogging.

Double check that when the shower is tepid or cool that at the same time the sink hot water is hot.

On 2017-02-21 05:03:07.687010 by Tammy

Ive lived in my 1700 sq ft rental home for 7 months. All was fine with both hot & cold water to kitchen, front bathroom sink & tub/shower as well as my master bath sink & shower. Then 3 months later Ione morning, I have no hot water in my shower but normal amount in my bathroom sink. The amount of water pressure is normal for both hot & cold, but temp for hot water gets no hotter than barely luke warm. Stays that way for 4 days and the 5th morning Ive got hot water

Happened again, still only in master bathroom, 2 months later but that time it was the sink as well as the shower. 6 days on that occasion, then bam, full hot water temp with nothing having changed that we are aware of.

Now 2 months have gone by and 3 days ago, again, no hot water in my master bath sink nor shower. Yhe following day, it is also only luke warm in the front bathroom tub & sink....but kitchen is perfectly normal temp.

We have a gas water heater that is not showing any signal lights that there is a problem. Please keep in mind, the amoubt of water pressure is mormal but the tempature is not.
Please....ANY ideas?

On 2017-02-21 04:26:13.394257 by Eric

We have a gas hot water heater. Worked fine during shower this morning. Had some power interruptions today, don't know if it's related. When I got home hot water flow was very restricted, very low pressure. Same all over house. Cold water is fine. Water is heating, turns hot if I let it trickle long enough. Pilot light is lit. Checked all circuit breakers. I would think it's a clog but it happened suddenly, while no one was using hot water, and while work in the area was causing power interruptions. Any ideas?

On 2017-01-07 16:31:39.399834 by (mod)

So there's a closed valve or a clogged, blocked pipe, elbow, shutoff, or faucet component on the hot water side. If the hot water is off on all of the bath fixtures then we can figure the blockage or shutoff is on a common hot water line ahead of where piping splits off to those individual fixtures.

On 2017-01-07 16:24:27.173893 by Jackie

2 story home with basement, all water hot and cold) working in the home, but one of the upstairs
baths has no hot water pressure

On 2017-01-01 19:58:10.864140 by (mod) - no hot water in just one bathroom

Losing water pressure only in one room is a helpful diagnostic as we know that it's not a system problem but rather a blockage close to the point of use. If both hot and cold water pressure is weak at a single faucet, start by removing the strainer to see if that's clogged.

On 2016-12-29 20:07:26.808638 by Laura

Sorry, outside "walk" should read "wall"

On 2016-12-29 20:06:07.075426 by Laura

We've had a sudden loss of water pressure but only for the hot water in kitchen. Kitchen sink is on an outside walk. Are going on vacation in a few days and will be away for a week. Outside temp has been zero or below since it's winter here. Just want to make sure this cannot indicate an emergency because we're happy to cope for now and to deal with it when we return.

On 2016-12-18 19:50:18.875346 by Paula

Have cold water in whole house but only one room has hot water other have no water coming out off hot water faucets. Electric water heater

On 2016-12-15 01:53:34.300643 by Anonymous

I cut through the 2 holes that go to the shower fascist in a trailer home,have replaced the holes there are no leaks anywhere but my hotwater pressure is so low the cold if perfectly fine.i Turned off the water heater yesterday do to low pressure,what could be causing the low hotwater pleasure???

On 2016-11-28 20:10:29.482896 by Sagar

We lose hot water pressure when a second source is opened. That is, I could be in the shower and if my wife turns on the faucet in the kitchen or bathroom, I lose hot water pressure/supply in the shower. Cold water pressure is just fine. Plumber tried to bypass the 40 gal water heater and connect cold water supply directly to hot line and the issue still existed. Any suggestions?

On 2016-10-26 01:44:54.665496 by Lynn

Ill try that, its a 40 gallon tank

On 2016-10-25 15:43:01.899216 by (mod) - no hot water even though replaced water heater

Start by watching the water heater when you're running hot water: is the burner on and running? Is the outlet pipe hot? How big is the heater?

On 2016-10-25 03:33:36.218161 by Lynn

Bought a brand new gas hot water heater, hot water only last about 5 mins in some areas and no hot water at all in other areas. however if you turn on sink in bathroom, shower will stay hot indefinitely upstairs and sometimes downstairs, seems like when other water is running somewhere in the house, some of the fixtures will be hot.

sooo confuse, had 3 plumbers look at it cant figure it out. bought a 2nd hot water heater 6 mos later,because they said it was the water heater, same problem.

On 2016-10-15 15:38:10.765166 by Terri

We lost water pressure due to a burst fridge supply line. Now we have no hot water in water tank, how do we get it to fill?

On 2016-08-04 21:04:21.761624 by (mod)

Sounds like an installation error on the hot water side, OR someone left a hot water control valve OFF.

On 2016-08-04 09:30:27.588940 by Chris

I have just replaced my bath taps for shower mixer , I have now lost pressure to the hot water only. The pressure to the sink is ok just the bath.

On 2016-05-28 11:31:43.153538 by Phil

Try turning on all the hot water taps It could be as simple as an air lock. Resolved my issue immediately.

On 2015-11-27 10:08:44.891253 by (mod) - where else to look to diagnose reduced hot water flow

I would check for debris clogged faucet strainer and shower head - keep in mind that a clog there will restrict both hot and cold water flow rate

On 2015-11-27 04:08:42.055258 by Anonymous

Hi both of the poor performing fixtures are new. The kitchen faucet was replaced in June. The shower head was replaced this month. I will look for the clogged valve or elbow or pipe in the water supply to the fixtures. Thank you.

On 2015-11-26 15:02:19.394663 by (mod)


As you have good hot water flow at other fixtures the problem is not a system issue but rather a clog unique to the poor-performing fixtures. Look for a mineral scale or debris-clogged strainer or faucet; if the flow is good when you remove a shower head or faucet strainer you've found the trouble. If not, then look for a clogged valve or elbow or pipe in the water supply to those fixtures.

On 2015-11-26 13:33:04.721009 by Jeanne Franzone

I have an indirect fired hot water heater with low hot and cold volume and pressure in my kitchen sink and my upstairs shower. All other faucets are fine. Plumbing and burner issues have been eliminated so we suspect the hot water heater. Any ideas on how to remedy this?

On 2015-11-17 03:11:14.836361 by (mod)

Nat that's odd I agree, and I'll give it some thought; perhaps a thermostastic control is not working properly.

See if you can identify what other water use, use of hot water, valve positions, correlate with the loss of hot water;

Is this a one family rental ?

As you're describing loss of water flow not water temp, it sure sounds like a blockage somewhere - perhaps a failed dip tube and debris clogging the water heater outlet.

On 2015-11-15 17:59:31.146505 by Nat - periodic loss of hot water

I'm having similar issues with the hot water at my rental unit, except my problem is periodic. Please let me know if you can provide any insight. My tenant describes the issue as follows, "Periodically we are losing hot water (barely a trickle) .

We noticed it's happening on the weekends after we do laundry, even on cold. It takes a good day before we get hot water again. Not sure if it's a combination of running the dishwasher and washing machine, however this has not happened before. This has been happening for about 3 weeks." Thank you


Continue reading at HOT WATER PRESSURE LOSS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see HOT WATER IMPROVEMENTS where we diagnose lost hot water pressure when cold water pressure is OK.

Suggested citation for this web page

HOT WATER PRESSURE LOSS FAQs at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Ask a Question or Search InspectApedia

Questions & answers or comments about diagnosing & repairing sudden loss of hot water pressure in buildings

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, 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.

Search the InspectApedia website

Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman