Start with the free checks: clean aerators and showerheads, verify all shutoff valves are fully open, and test pressure at the hose bib. These three steps resolve the majority of low-pressure complaints without a plumber. If pressure is low at the hose bib (below 45 PSI), the cause is the PRV or municipal supply — that's a plumber call. If the hose bib pressure is normal but indoor fixtures are weak, the restriction is inside the house.
The right fix for low water pressure depends entirely on the cause. A $0 aerator cleaning and a $12,000 repipe are both valid answers — for different problems. This guide ranks every fix from cheapest and easiest to most involved, and tells you which cause each one addresses so you don’t spend money solving the wrong thing.
How Do I Increase Water Pressure in My House?
The approach depends on what’s causing the low pressure. Here’s a ranked list from free to expensive:
| Fix | Cost | Cause it addresses |
|---|---|---|
| Clean aerators and showerheads | $0 | Mineral buildup at fixtures |
| Open shutoff valves fully | $0 | Partially closed valves |
| Adjust PRV set screw | $0–$175 | PRV set too low |
| Replace PRV | $250–$450 | Failing PRV |
| Install pressure booster pump | $400–$900 | Genuinely low incoming pressure |
| Flush water heater | $0–$150 | Sediment reducing hot-side flow |
| Descale copper pipes | $200–$450 | Moderate scale inside copper |
| Repipe galvanized lines | $8,000–$15,000 | Severely corroded galvanized pipes |
Work from the top of that list downward. Most low-pressure problems are resolved in the first three rows.
Can I Fix Low Water Pressure Myself or Do I Need a Plumber?
Depends on the cause. DIY-capable fixes:
- Cleaning aerators and showerheads — no tools, 20 minutes, anyone can do it
- Opening shutoff valves — identify the valve, turn it to fully open, done
- Flushing the water heater tank — DIY-capable, but don’t do it on a tank that’s never been flushed if it’s over 10 years old (see mineral buildup article)
Fixes that need a plumber:
- PRV adjustment — adjustable by a confident DIYer with a gauge, but one wrong move sends pressure to dangerous levels; most homeowners are better off paying for a service call
- PRV replacement — requires shutting off the main, soldering or press-fitting copper fittings; licensed work in most WA municipalities
- Pipe descaling or repiping — always a licensed plumber job
Use the DIY or Pro tool if you’re unsure whether your specific situation warrants a plumber.
Low Water Pressure Quick Fix Before Calling a Plumber
If you need to improve pressure quickly while you wait for a plumber appointment, three things can help immediately:
- Clean the aerators on the worst-affected fixtures — this takes 20 minutes and often produces a noticeable improvement even if it doesn’t fully solve the underlying problem
- Check every shutoff valve in the house — main shutoff, branch shutoffs under sinks, and the water heater inlet valve. Make sure all are fully open.
- Run the outdoor hose bib without the hose — if outdoor pressure feels strong but indoor pressure is weak, the restriction is definitely inside. This narrows the problem for the plumber and shortens the diagnostic.
If indoor and outdoor pressure are both weak, call your water utility first before the plumber — it may be a municipal issue they’re already aware of.
How to Boost Water Pressure Without a Plumber
Three non-plumber options for genuinely low supply pressure:
1. PRV adjustment (confident DIYers only)
The PRV has an adjustment screw on top, under a locknut. With a pressure gauge attached to the hose bib, loosen the locknut and turn the screw clockwise in small increments — half turns — checking the gauge after each. Stop at 60–65 PSI. Do not exceed 80 PSI. Re-tighten the locknut.
2. Showerhead upgrade
Replacing a standard showerhead with one designed for low-pressure homes (pressure-compensating models) improves spray intensity without changing actual supply pressure. See our shower pressure guide for specific recommendations.
3. Remove flow restrictors
Kitchen and bathroom faucets often have 1.0–1.5 GPM restrictors. Removing them increases flow rate. This doesn’t fix pressure — but it improves the experience at low-pressure fixtures.
WARNING: Do not adjust the PRV without a gauge attached. Without feedback, it’s easy to overshoot 80 PSI — the level where pipe stress and fixture damage accelerate. A $15 gauge is mandatory for this job.
Water Pressure Booster Pump — Is It Worth It?
A booster pump is worth considering when:
– Supply pressure at the meter is consistently below 45 PSI (confirmed by gauge)
– The cause is municipal supply, not a fixable home plumbing issue
– PRV adjustment can’t help (some municipalities supply at below-normal pressure)
A booster pump installs on the main supply line and amplifies incoming pressure. Systems run $400–$900 for the pump unit; installation adds $250–$500 in labor in Seattle (2026).
When it’s not worth it:
– If the cause is corroded galvanized pipes — a booster pump pushes more water through the same narrowed pipes; it doesn’t fix the restriction
– If the cause is a clogged aerator or low-set PRV — fix those first; a booster pump is expensive and unnecessary
Get a plumber to confirm the cause before purchasing a booster pump. Spending $1,000–$1,400 installed and then discovering the PRV was just set wrong is a frustrating outcome.
How to Fix Low Water Pressure in Shower Only
Shower-specific low pressure almost always comes from the showerhead or the shower valve, not the supply system. Fix in this order:
- Clean the showerhead — vinegar soak overnight, then scrub nozzles
- Remove the flow restrictor if pressure remains low after cleaning
- Test flow at the bare arm — remove the showerhead entirely and turn on the water. Strong flow at the arm = showerhead problem solved. Weak flow at the arm = valve or supply issue.
- Replace the shower cartridge — if flow at the arm is weak, the cartridge inside the shower valve body is the next likely cause ($125–$275 with a plumber)
For a full walkthrough of shower-specific pressure fixes, see our shower water pressure guide.
Low Water Pressure in Upstairs Bathroom — How to Fix It
Upper-floor low pressure has two likely causes: elevation pressure loss or pipe restriction.
Elevation loss: Water pressure naturally drops approximately 0.43 PSI per foot of elevation. An upstairs bathroom 10 feet above the main floor has roughly 4–5 PSI less pressure by physics alone. In a home with 50 PSI at the main, the upstairs bathroom naturally gets 45–46 PSI — marginal but functional.
If the pressure drop between floors is greater than 5–7 PSI, there’s a restriction somewhere in the supply branch to the upper floor. In older homes, that branch is often smaller-diameter galvanized pipe that has narrowed.
Fixes:
– If the whole-house pressure is low, address it at the source (PRV or supply)
– If only the upper floor is affected, have a plumber inspect the branch supply pipe serving that floor
– In severe cases, running a new ¾-inch supply branch to the upper floor restores full pressure without a full repipe
Fixing Low Water Pressure in an Older Home — Options
Older homes in WA — pre-1960s construction — typically have one or more of these pressure problems:
- Galvanized pipes: Progressively narrowed by corrosion. Only fix is repiping.
- Original PRV: If the home has a PRV installed decades ago and never serviced, it may be set too low or failing. Replace it ($250–$450 in Seattle).
- Undersized supply: Homes built before modern water demand norms sometimes have ½-inch or ¾-inch mains where 1-inch or larger is now standard.
- Mineral scale in copper: Homes with copper pipes installed 40+ years ago may have significant scale buildup; descaling may help.
The pragmatic approach: test pressure at the main first. If you’re getting 60 PSI at the hose bib but weak pressure inside, the problem is pipes. If you’re getting 35 PSI at the hose bib, start with the PRV.
How to Fix Low Water Pressure from Galvanized Pipes
There is no in-place fix for severely corroded galvanized pipes — the corrosion buildup inside the pipe is structural and cannot be reversed. Options:
Repiping: Replace galvanized supply lines with copper or PEX. This is the only permanent solution. In Seattle, a full repipe runs $8,000–$15,000 for a typical single-family home. Phased repiping (replacing the worst branches first) is available for homeowners who want to spread the cost.
Galvanized-to-PEX conversion: Many Seattle plumbers now offer PEX repiping as a less expensive alternative to copper. PEX is flexible, doesn’t corrode, and resists mineral scale. Cost runs $6,000–$12,000 for most Seattle homes — less than copper.
Pipe lining (limited use): Epoxy pipe lining can coat the interior of supply pipes to stop corrosion and reduce further narrowing. It’s a newer technology not widely offered in the Seattle area, more common in commercial applications, and not a substitute for repiping in severely affected pipes.
A plumber can run a flow rate test to quantify how much capacity you’ve lost and whether repiping is urgent or can be deferred.
Low Water Pressure Temporary Fix While Waiting for a Plumber
If you’re waiting for a plumber appointment and need to use the house in the meantime:
- Prioritize which fixtures matter most — if the shower is too weak to use, the kitchen sink may still be functional. Route around the worst-affected areas temporarily.
- Clean aerators on usable fixtures — even if you haven’t fixed the underlying cause, removing aerator restriction gives you whatever pressure the system can deliver
- Fill buckets or containers during off-peak hours — municipal pressure is usually highest between 10 PM and 6 AM; fill what you need during that window
- Avoid simultaneous high-demand use — stagger dishwasher, washing machine, and shower use to minimize demand-related drops
None of these fix the problem, but they make a low-pressure home livable while you wait for the repair.
FAQ
Q: What is the cheapest way to fix low water pressure?
A: Clean your aerators and showerheads first — it’s free and fixes the problem in a large percentage of cases. If that doesn’t work, confirm all shutoff valves are fully open. If pressure is still low, test at the hose bib with a gauge ($15) to determine whether the cause is the supply system or the pipes.
Q: How long does it take to fix low water pressure?
A: Minutes for an aerator cleaning. 20–30 minutes for a plumber to adjust a PRV. 1–2 hours for PRV replacement. Several days for a full repipe. The timeline is determined entirely by the cause.
Q: How much does it cost to fix low water pressure in Seattle?
A: Free for DIY aerator cleaning. $95–$175 for a plumber diagnostic visit. $250–$450 for PRV replacement. $400–$900 for a booster pump (plus installation). $8,000–$15,000 for a full repipe. Use the cost estimator for a detailed estimate based on your situation.
Q: Will a plumber find the cause of low pressure in one visit?
A: Usually yes. A pressure gauge test, a quick inspection of the PRV and main shutoff, and a walk-through of the affected fixtures gives a plumber enough information to identify the cause in most cases. Have your hose bib accessible and note which fixtures are affected before they arrive.
Q: Does fixing low water pressure require a permit in Washington?
A: PRV replacement and pipe work typically require a permit from your local building department (SDCI in Seattle, or your city’s equivalent). A licensed plumber will pull the required permits as part of the job. DIY PRV adjustment without replacement doesn’t require a permit.
Still not sure?
Use our DIY-or-Pro tool to decide in under a minute, or get a free cost estimate for your WA city.