Plumbing in the Home/water pressure low


I've checked the water pressure at the tap on the wall outside the house and am getting 80 pounds, which is sufficient. However, when I turn on a tap inside the house, the pressure is very low. There is no leak under the house so I can't figure out what the problem could be. The piping coming into the house is a black flexible hose. The piping throughout the house is a plastic (I assume pvc) piping of some sort. The house was completely replummed a few years back to replace the polybutylene (sp?) piping that was installed originally. I had good pressure until the last few months. To me the only option would be something blocking the water, but I don't see how anything could get into the piping. Any ideas?

Hello Rubye,

I think you, like many are confusing the difference between low flow of water versus low pressure. I'm sure if you tested the pressure inside the house, such as at the washing machine faucets that have hose connections you would find that the pressure was the same inside the house.

While it is possible that something has gotten into the piping system and block something, the pressure would be the same but the flow rate would drop drastically.

Most plumbing fixtures these days have flow restrictors built into them for water conservation reasons. Showerheads are typically restricted to 2.5 gallons per minute. Lavatory and kitchen sink faucets are restricted to 1.5 gallons per minute. Other things like toilets, tub spouts and washer machines do not have restriction.

What may be happening here is that the aerators on the ends of your faucet spouts may be getting clogged up with tiny debris or hard water scale. These can typically be unscrewed and cleaned out or inexpensively replaced. I think that if you remove the aerator and run the faucet in question, you will probably see that the flow rate is fine and that it is the aerator that is causing the problem.

Another possibility is that if you have a pressure regulator on your water system, the regulator may be failing and not delivering the maximum flow rate that it should be. If the faucet aerators are not the problem, this would be the next thing I would look at or have a professional look at.

Good Luck,

Plumbing in the Home

All Answers

Answers by Expert:

Ask Experts


Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


Retired, Licensed General Contractor with Plumbing license. Active Home Inspector, Litigation Consultant and Infrared Thermographer, Online Marketing specialist.

Publications "Rain Maker" as "Inspector Dana", about making money online.

30+ years in the building trades, Licensed General Contractor (Retired), Certified Infrared Thermographer Internet Entrepreneur, Amazon & eBay Merchant (deals-by-dana)

Awards and Honors
Listed FHA Fee Inspector, FHA 203(k)Consultant, HUD Mobile Home Inspector

Past/Present Clients
Home buyers, sellers and owners, Investors, Commercial roofing companies (infrared roof scans for moisture intrusion, Litigation Consulting for "Slumlord" laws in SoCal

©2017 All rights reserved.