If water is weak at nearly every faucet, shower, and outdoor spigot, treat it as a whole-house problem rather than a clogged aerator. Start by comparing hot and cold water, checking whether neighbors or your utility report a supply issue, checking whether the accessible customer-side main shutoff is in its intended operating position, and recording a static pressure reading if you can do so safely.
This guide is for a broad loss of flow or pressure across a home. If only one faucet is affected, use our one-faucet low-flow guide. If only the shower is weak, use the shower-only troubleshooting guide. To measure actual pressure, follow How to Test Water Pressure at Home.
First decide whether the whole house is really affected
Pressure and flow are related but not interchangeable. The Portland Water Bureau notes that a home can have normal pressure but poor flow because of restrictions such as clogged fixtures or corroded piping. Before assuming the utility pressure is low, compare several outlets.
| What you observe | More useful next check |
|---|---|
| One faucet or shower is weak; others are normal | Use the one-faucet checks or shower-only checks. |
| Hot water is weak but cold water is normal | Use the hot-only low-flow guide and report the pattern to a plumber or property manager; it calls for a water-heating-side investigation. |
| Hot and cold are weak at many fixtures, even with one outlet running | Start with utility and neighborhood conditions, then the accessible household shutoff, filter, regulator and leak checks below. |
| The whole house suddenly loses pressure or has no cold water | Use the sudden-pressure-loss checks to contact the utility or property manager and check official notices. Follow any local advisory. |
| Many outlets feel weak at recurring times, then return to normal | Record the time pattern and comparable gauge conditions before assigning a cause. |
| One outlet works normally; flow falls when another fixture runs | Use the pressure-drop checks for simultaneous water use and label the test conditions. |
| Flow has declined gradually, or a static reading seems normal but flow is weak | Read about restrictions and poor flow despite normal static pressure; a reading alone cannot identify the blocked component. |
Apartment or shared building supply? Report which outlets and units are affected to the property manager. For a private well or booster system, use the responsible technician; this guide does not cover pump controls.
Check for a utility or neighborhood pressure problem
No water at any cold tap? Use the no-water-at-the-faucets guide to check service notices, distinguish hot-only loss, and prepare a utility or building service report.
A sudden whole-house change can begin outside the home. Utilities may lower pressure because of a main break, pumping problem, maintenance, or a pressure-zone event. If neighbors are affected too, or if the utility has issued an advisory, do not start replacing household plumbing parts.
A neighbor with normal water does not establish the expected pressure at your address. Elevation and the utility pressure zone can affect supply pressure, even on the same street. Ask your utility for the expected static pressure range at your property rather than treating a neighbor’s reading as a target.
If pressure returns but the water looks different, keep following the provider’s current water-use instructions. Use the brown-water observation guide for rusty or colored water, or the cloudy-water guide for white or milky water. Appearance notes help describe the problem; they do not establish that the water is safe to use.
What to tell the utility about low water pressure
- Your service address, when the change began, and whether it is constant or occurs at certain times.
- Whether all cold taps are affected, whether hot water differs, and any official notice or nearby work.
- Any pressure readings already obtained safely, with time, gauge location, and whether water was running. Say if the location relative to a PRV is unknown.
Ask: “What static pressure range is expected for this address, are there current supply issues, and what should I do next?” Do not delay reporting a sudden loss of cold water to complete this list.
If cold water is normal but several hot outlets are weak, use our hot-only low-flow troubleshooting guide before treating the problem as a utility-wide pressure loss.
Portland Water Bureau advises checking all faucets and comparing hot and cold water when pressure or flow changes. If you have no cold water anywhere, contact the utility or property manager after checking for a shutoff notice or visible work nearby. A sudden major loss of distribution pressure can also trigger public-health guidance, so follow any local utility advisory rather than relying on a general DIY article.
Check the customer-side main shutoff without forcing it
A partially closed household shutoff can reduce flow throughout the home. If you can safely identify the accessible customer-side main shutoff, check its intended operating position using its instructions or a plumber’s guidance. Do not assume a multi-turn valve is open from its handle position alone. Never reopen plumbing intentionally shut off for a leak, repair, vacancy, or another safety reason. Do not force a stiff or corroded valve. Our main water shutoff guide explains how to locate and label it.
If the valve will not move normally, leaks at the stem, or appears damaged, stop and call a plumber. Do not operate a utility-owned curb stop unless your water provider specifically permits it.
Look for a pressure-reducing valve or whole-house filter
Many homes have a pressure-reducing valve (PRV) near the point where the water service enters the building. Portland Water Bureau specifically lists a PRV and whole-house filter among the things to check when flow is reduced at all faucets. A clogged filter or a pressure-control problem can affect many fixtures at once.
Do not turn a PRV adjustment screw simply because the shower feels weak. The installed model, incoming pressure, downstream pressure, thermal expansion, and local plumbing requirements all matter. If you find a PRV, photograph the model label and record pressure before asking a plumber to adjust or service it.
For suspected regulator trouble, use the pressure-regulator symptoms guide to record the model and observations before requesting service.
Check for visible leaks and unexplained meter movement
A leak can reduce available pressure or flow, especially if it is large. Walk the accessible plumbing route for active water, damp supply connections, unusual running-water sounds, or water where it should not be. If there is no visible leak, a no-use meter observation can help determine whether water is moving through the meter while normal use is stopped.
Use our water meter leak test for a documented observation. A changing meter can support a leak investigation, but it does not locate the leak by itself.
Measure service pressure instead of guessing
EPA WaterSense recommends about 45 to 60 psi for efficient fixture operation and describes measuring static pressure at a hose connection with water use stopped. This is guidance, not a universal pass/fail threshold or a diagnosis of a leak.
Before buying or borrowing, use the gauge shopping checklist to confirm permitted water service, matching connection threads, and a readable pressure scale. Then follow the five steps for using a water-pressure gauge. Record the time, connection location, psi and whether water was running. Note whether that connection is before or after a regulator; if unknown, write “unknown.” An outdoor reading may not represent the indoor supply. The measurement guide explains static versus flowing readings.
Consider pipe restrictions if pressure is normal but flow is poor
Normal static pressure with weak flow at many outlets can point toward a restriction rather than low incoming pressure. Portland Water Bureau notes that older galvanized plumbing can develop internal corrosion that reduces flow. Whole-house filters, strainers, partially closed valves, and other restrictions can produce a similar pattern.
Do not assume a repipe is necessary from symptoms alone. A plumber can compare pressure at different points and under different flow conditions before recommending invasive work.
When to call the utility and when to call a plumber
- Call the utility or property manager for a sudden area-wide change, no cold water at multiple fixtures, known main work, or an official pressure advisory.
- Call a plumber when the problem appears limited to the property, a PRV/filter/service valve may be involved, there is an active leak, or static pressure readings need professional interpretation.
- Stop routine testing for flooding near electrical equipment, contaminated water, a broken service line, or a valve that is leaking when touched.
Frequently asked questions
Can one clogged faucet cause low pressure throughout the house?
No. A clogged aerator or fixture restriction usually affects that outlet. If many outlets are weak, compare the main supply, PRV, filters, leaks, and pipe condition.
Should I adjust the pressure regulator myself?
Not from symptoms alone. Record the installed model and pressure readings first. Incorrect adjustment can create high pressure or hide another restriction.
Is 40 psi always too low?
Not necessarily. Utility pressure varies by location and elevation. EPA WaterSense recommends 45–60 psi as an efficient service-pressure range, while utilities may operate broader ranges. Use your local utility information and actual household measurements.
Sources and related guidance
- EPA WaterSense: Home Maintenance — Service Pressure
- Portland Water Bureau: Troubleshooting Water Pressure and Flow
- Moen Solutions: Low Water Pressure
Research-based educational guide. Local plumbing codes and utility conditions vary. See our Editorial Policy and Disclaimer.
