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Bellingham Home Inspector (King of the House) Water Pressure

By Steven L. Smith

Home Inspector with King of the House Home Inspection, Inc. Home Inspector Lic #207

March 09, 2011 03:29 PM

When doing a home inspection, I always check the water pressure when it is possible to do so. Sometimes I use the outside faucet. Other times I have used a laundry faucet and I even have a little gizmo that allows me to attach my pressure gauge to a bath or kitchen sink.

It is amazing how often one finds that the water pressure is too high -- over 80 psi and how often it is too low -- below 40 psi.

Around here, most plumbers set the pressure at about 50 psi, a bit higher in a multi-story house. On the other hand, I have heard people complain that they thought they had marginal pressure when it was in that range. That, of course, can be related to other problems too, like old rusted pipes.

Many times there is a pressure reducing valve in the system and it can be adjusted up or down. Other times, the pressure is low but that is just plain as good as it gets or they have to discuss a potential remedy with a plumber. And, if the pressure is too high, which can damage valves and appliances, then a pressure reducing valve is usually the way to go.

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Tony Orefice

NorthGroup Real Estate/www.TonyORealtor.com - Concord, NC

Realtor- Cabarrus County, NC

Steve,

our house was built with a pressure reducing valve attached. How you doin'?

Mar 09, 2011 11:05 PM

Jay Markanich

Jay Markanich Real Estate Inspections, LLC - Bristow, VA

Home Inspector - servicing all Northern Virginia

I have a tester that does pressure as well as gallons of flow per minute, which I use on houses with wells.

Mar 09, 2011 11:09 PM

Michele Miller ~ REALTOR®, LMC, HSE, CHS, SRES, CMRS

ERA Key Realty~Worcester County Realty Group - Worcester, MA

'Helping You Make the Best Move"

I had a well run dry after the home inspector ran it for 3 hours. Became a real issue before the closing.

Mar 09, 2011 11:42 PM

Jim Mushinsky

Centsable Inspection - Framingham, MA

Hi Steve - I think of excessive water pressure as mainly an nuiscance from splashing over-spray. Residential copper pipe is typically rated for about 4,000 psi. Additionally a common nuisance is dripping at the water heater TPR valve. Watts TPR water heater valves typically relieve pressure at 150 psi.

I am not familiar with damage around the 80 psi level. If you have some info, please send it along.

Thanks - Jim

Mar 10, 2011 07:49 AM

Steven L. Smith

King of the House Home Inspection, Inc. - Bellingham, WA

Bellingham WA Home Inspector

Jim,

I would categorize dripping at the TPR valve as more than a nuisance, that being an emergency valve not designed for continual use. Since 80 is the ballpark high end I would think there would be fewer problems at that level. I have had plumbers tell me that they prefer 50 to 60. They are not specifically looking at what you are talking about, more things like valves in dishwashers, toilets, that sort of thing. Here is an article and again, I am sure that the higher the more problems, but above 80 is the official cutoff for acceptable pressure, so that is why it is the high end per code and general guidelines. http://www.inspectapedia.com/water/Water_Pressure_Too_High.htm

Mar 10, 2011 08:17 AM

Dale Ganfield

Leland, NC

Hi Steve, like you I measure the incoming pressure when I can and advise to adjust appropriately when low < 40 psig and high >70 psig and prefer to be within the target range of 50 - 60 psig. My understanding is that high water pressure can be a cause of water hammer and early failure of automatic valves.

Mar 10, 2011 09:15 AM

Donald Hester

NCW Home Inspections, LLC - Wenatchee, WA

NCW Home Inspections, LLC

Good information. A High pressure are hard on valves, especially as they age.

I would like to know why an inspector would run it for 3 hours as Michele reported.

I have a well but running dry is not an issue it produces over 25 gal/min.

Mar 10, 2011 02:03 PM

Charles Buell

Charles Buell Inspections Inc. - Seattle, WA

Seattle Home Inspector

Steve there are good reasons why the "minimum" standards of the plumbing code require that the pressure not be over 80 PSI. There are a multitude of reasons for this but the focus is on protecting the fittings and fixtures and appliances connected to the plumbing supply. High pressures are hard on solenoid valves in appliances as well as the rubber seals in shut-off valves/faucets. If hammering occurs the higher pressures exacerbate the effects of the hammering. House pressure at 80 PSI or 100 psi or 120 PSI when heated increases the pressures in the pipes---especially when expansion devices are not in place or have failed. But aside from all of this the code says it can't be over 80 PSI and that is good enough for me---and I am content to rely on that to back up my recommendation for repairs when it is above 80 PSI.

Mar 10, 2011 05:01 PM

Michelle and Don,

That is a complete well draw-down which is not something I want to do. I once did a house with a well and the setpic guy ran the water for an hour and the well went dry. I was accused of having run it dry but got it worked out. Sopmetimes they do that to determine the well's capacity. But that is typically done by well professionals and, unless a home inspector is in that category, he should not empty the wll by running water for hours.

Mar 11, 2011 01:41 AM

Charlie,

Same here.

Mar 11, 2011 01:42 AM

Bellingham Home Inspector (King of the House) Water Pressure

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