Your water pressure has dropped
One tap or the whole house? That fork decides everything.
Is this an emergency?
Plan it in. No damage clock running.
You’re probably seeing
- Weak flow at every tap in the house
- One tap or shower noticeably weaker than the rest
- Pressure that drops sharply when a second fixture is used
- Hot water weak while cold is fine, or the reverse
- Pressure that has declined gradually over months or years
What it probably is
A clogged aerator or showerhead
The most common single-fixture causeOne fixture only. Unscrew the aerator and you will usually find grit and mineral scale. The cheapest fix in plumbing.
A failing shut-off or main valve not fully open
Common and free to checkWhole house, often after recent plumbing work or a meter replacement. Someone closed a valve and did not reopen it fully.
A failed pressure reducing valve
Common where fitted - and widely overlookedWhole house, and often gradual. The PRV is a bell-shaped brass fitting near where the supply enters, usually with an adjustment screw. It is a wear part with a finite life.
A clogged whole-house filter or softener
Common where one is installedWhole house, gradual, and the filter cartridge has not been changed on schedule. Softeners can also channel or clog internally.
A failing fixture cartridge or valve
Common on older mixersOne fixture, with hot and cold behaving differently, or a mixer where one side is weak.
Corroded galvanised supply pipe
Common in older housing stock - and the expensive oneWhole house, very gradual over years, in a home with original galvanised steel piping. Interior rust progressively narrows the bore.
A municipal supply issue
Less common, but free to rule outWhole house, sudden, and neighbours have it too. Worth one phone call before spending anything.
What to do before anyone arrives
Test every fixture, hot and cold separately
Two minutes with a notebook. One weak fixture is a fixture problem. All fixtures weak is a supply problem. Hot weak everywhere but cold fine points at the water heater or its shut-off rather than the house supply.
If it is one fixture, clean the aerator
Unscrew the tip of the tap - usually by hand or with cloth-wrapped pliers - and rinse out the screen. Showerheads unscrew the same way and can be soaked to dissolve scale. This resolves a large share of single-fixture complaints for nothing.
If it is the whole house, check the main shut-off is fully open
Find the main valve and confirm it is fully open, not part-turned. Check the meter valve too if it is accessible. This is genuinely common after any work on the system.
If a valve is stiff, do not force it. Old gate valves break, and a broken main valve is a much worse afternoon.
Check whether anyone else is affected
Ask a neighbour, or call the water utility. A supply-side problem is not yours to pay for, and it takes one call to rule out.
Look for a pressure reducing valve near the supply entry
A bell-shaped brass fitting with an adjustment screw, usually close to the main shut-off. Not every home has one. If yours does and whole-house pressure has faded gradually, that part is a strong suspect - and it is a component replacement, not a repipe.
Do not adjust a PRV by guesswork. Raising pressure without a gauge can push the system past what fixtures and the water heater relief valve are designed for.
Change the whole-house filter if you have one
A neglected sediment filter is a very common cause of gradual whole-house decline, and replacing the cartridge is routine homeowner maintenance.
This is the end of the homeowner sequence. Pressure testing, PRV replacement and any assessment of corroded supply pipe are plumber work.
What it costs to fix
Ranges below are for the repair itself. For full replacement pricing see the plumbing cost guides.
| What it is | Whose job is it? | What decides your bill |
|---|---|---|
| Cleaning an aerator or showerhead | Yours | Free |
| Opening a partly closed valve | Yours | Free |
| Replacing a filter cartridge | Yours | The cartridge |
| Fixture cartridge replacement | Plumber, or a confident homeowner | The part, plus a short visit |
| Pressure reducing valve replacement | Plumber | A modest part plus labour - far cheaper than a repipe |
| Repiping corroded galvanised supply | Plumber | A project. Get more than one opinion |
U.S. Bureau of Labor Statistics, Occupational Outlook Handbook (May 2025 wage data).
The spread here is enormous - from free to a whole-house project - which is exactly why the one-fixture-or-everywhere test matters before anyone quotes. A specific caution: if whole-house pressure has declined gradually and the first recommendation is a repipe, ask whether the pressure reducing valve and any whole-house filter have been checked and what the measured static pressure actually is. Labour anchor: the national median wage for plumbers, pipefitters and steamfitters is $30.67 an hour (BLS, May 2025).
Can I fix this myself?
Low pressure is rarely a safety problem, but two related things are. Do not force a stiff old main valve - breaking it turns a minor complaint into an emergency shut-off you no longer have. And do not wind up a pressure reducing valve to compensate for poor flow: excessive pressure stresses every joint, fixture and appliance in the house and can push a water heater relief valve into discharging.
Reasonable to DIY
- Testing every fixture, hot and cold
- Cleaning aerators and showerheads
- Confirming the main shut-off is fully open
- Replacing a whole-house filter cartridge
- Calling the utility to rule out a supply issue
Call a pro
- Measuring static and dynamic pressure properly
- Replacing or adjusting a pressure reducing valve
- Diagnosing a failing water softener
- Assessing corroded galvanised supply
- Any repipe or main line work
A surprising share of low-pressure complaints end at an aerator full of grit or a valve someone left half closed, and both of those are free. Work the fork first. If the whole house is weak and it happened gradually, make sure the pressure reducing valve and the filter have been ruled out before anyone starts talking about pipes - those are component replacements, and a repipe is not.
Is this covered by insurance?
Whether a claim is worth filing depends on the cause, your deductible and how the damage happened - not on the repair price alone.
Sources
Sources last checked
- Plumbers, Pipefitters, and Steamfitters - median pay, May 2025U.S. Bureau of Labor Statistics, Occupational Outlook HandbookRetrieved 2026-09-14
- Tap Water Scalds (CPSC Publication 5098)U.S. Consumer Product Safety CommissionRetrieved 2026-09-14
Sources for the figures and the legal requirements cited on this page.
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