Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER CONSERVATION MEASURES
WATER CONTAMINANT LEVELS
WATER FILTERS, HOME USE
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL CHLORINATION & DISINFECTION
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
How to improve bad city water pressure: This article describes how to boost or improve poor city water pressure or flow in a building by adjusting the pressure regulator, replacing small or clogged piping, or installing a water pressure booster pump.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
Diagnose Water Pressure Problems Before Starting to "Fix" Them
Before taking any costly steps to install a booster pump or dig up and replace piping, start at the beginning of this article series: WATER PRESSURE LOSS DIAGNOSIS & REPAIR
or at MUNICIPAL WATER PRESSURE DIAGNOSIS to be sure that there is not something to fix in the building water supply piping, water service entry piping, or simply a leak or a valve that is partly shut.
Check and Adjust the Water Pressure Regulator
Before adjusting the water pressure regulator (center of our sketch at left, changing building piping, or considering installing a water pressure booster pump , it is essential to understand what the incoming water pressure is and exactly why the building water pressure is not satisfactory.
[Click to enlarge any image]
Sometimes, even when residential water supply equipment is working normally, building occupants want higher water pressure.
Don't confuse water quantity (how much before we run out), water flow (how many gallons per minute we can get at a faucet) and water pressure (what is the delivery pressure or the maximum pressure that the system can provide). Water pressure is measured most accurately with the water turned off, at a hose faucet or washer hookup, using a pressure gauge.
But in common language, people consider the strength of flow at the faucet as their "water pressure". Actually what is being observed is a water flow rate, determined by both the pressure from the water source and the diameter of the building piping, including the effects of any obstructions.
Definitions of Water Pressure, Water Flow Rate, & Water Quantity
Water quantity is the total amount of water that is available at a building. For most city water supply systems the water quantity at a home is not limited, though in some areas of limited municipal water quantity, water may be provided by the city water mains only during certain hours of the day, or city water pressure may vary during some times of the day such as during periods of heavy usage. For people whose buildings are served by a private well system, water quantity is a local and significant question. (See WELL FLOW RATE).
Definition of Building Water Pressure - Static Water Pressure
The Home Reference Book points out that people like to have lots of water flow and pressure at faucets. Water flow (in gallons per minute) is a function of several things, including the size and shape of the faucet opening, and the pressure at the faucet. The pressure at the faucet is a function of the pressure available from the source, and the pressure lost moving the water through the pipe to the faucet. Typically, city water supplies are at 40 to 70 psi (static pressure).
Psi means Pounds per square inch, and is a common way of measuring water pressure. Pressure loss in the home is due to elevation (we lose pressure when we push water up from one story to the next) and friction as water flows through piping. Larger pipes lose less pressure due to friction.
Static pressure is exerted by the water against the pipe walls with no water flowing. Here’s a simplified (and not 100% accurate) way to look at it. A 100-foot long horizontal pipe connected to a 60 psi supply will have a pressure of 60 psi anywhere along the pipe, with no flow.
As water begins to flow, the pressure drops. This is a result of friction loss along the pipe walls. If gauges were put on the pipe every ten feet, the gauge at the source would still read 60 psi, and (depending on the pipe diameter and the amount of water flowing), the gauge ten feet from the source might read 58 psi; the gauge twenty feet down would read 56 psi, the next gauge 54 psi, et cetera. At the faucet, the pressure might be 40 psi.
As the water flow increases, the pressure drops more at each point along the pipe. The water pressure at the source (city water main) will remain at 60 psi. The amount of pressure lost due to friction as water flows depends on the pipe diameter and the amount of water flowing. With several faucets open, the flow at each faucet may be weak and there may not be enough pressure for a shower, for example.
Diagnose & Fix Clogged Water Piping or Closed Water Valves
Before changing building water piping diameter or adding a water pressure booster pump (solutions discussed below), check that you don't have a repairable problem with the present water supply piping and or valves in the building.
Here are some things to check:
Install Larger Diameter Water Supply Piping
A common "fix" for poor building water "pressure" (really flow) where the piping is blamed, is to install larger diameter water supply piping wherever the piping is readily accessible, such as in a basement or crawl area.
As more plumbing fixtures flow, the pressure and flow drops more at each fixture.
If we replace any ten-foot section of pipe with a larger pipe, the pressure drop across that section will be reduced.
Replacing any section of pipe improves pressure (and flow) throughout the system.
Add a Water Pressure Booster Pump
Adding a local municipal water pressure booster pump and a larger water pressure tank in a building with poor municipal water supply pressure will improve local water pressure in the building give a longer water draw-down time between booster pump "on" cycles, which means if your pressure normally ranges between 30 and 50, it will fall from 50 down to 30 more slowly.
It won't boost system pressure beyond the control setting.
If you set the control too high the pump will not reach cutoff temp and will burn up, or if you put in a more powerful pump and boost much over 70 psi you risk plumbing leaks.
Adding a booster pump can improve building water pressure where incoming municipal pressure is low (MUNICIPAL WATER PRESSURE DIAGNOSIS), where the private pump and well system can't get enough pressure or quantity (WELL WATER PRESSURE DIAGNOSIS) or where the building height impacts water pressure on its upper floors.
See WATER PRESSURE BOOSTER PUMP for details.
Our discussion of water pressure and flow diagnosis is divided into water pressure loss symptoms and diagnostic steps for MUNICIPAL WATER PRESSURE DIAGNOSIS and separately, WELL WATER PRESSURE DIAGNOSIS - we give procedures for both municipal water supply problems and well water supply problems.
The process of diagnosis and the costs of the repair when municipal water supply, quantity, or flow are poor are explained here.
Separately we also provide a WATER PRESSURE PROBLEM DIAGNOSIS TABLE in table format listing nearly every cause of water pressure loss or well pump problem identification, diagnosis, and repair. Our sketch at page top, courtesy of Carson Dunlop, shows the key components found where municipal water supply enters a building.
Continue reading at MUNICIPAL WATER PRESSURE DIAGNOSIS or select a topic from the More Reading links shown below.
Suggested citation for this web page
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs) about how to improve municipal or city water pressure & flow rate
Questions & answers or comments about how to improve weak city or municipal or community water pressure & flow rate.
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
HTML Comment Box is loading comments...
Technical Reviewers & References