How Can You Increase Water Pressure in Your House? (And Why Is It Low?)

A practical diagnostic guide — from a two-minute aerator clean to knowing when to call a plumber.

You turn on the shower and stand under what feels like a polite drizzle. You run the kitchen tap while the dishwasher is going and watch the flow drop to a trickle. Your washing machine takes forty minutes to fill. Meanwhile, your neighbor seems to have perfectly normal water pressure and no idea what you’re complaining about.

Low water pressure is one of the most universally frustrating household problems — partly because it affects everything you do with water, and partly because it can have a dozen completely different causes, from a partially closed valve to a failing municipal supply line. The good news is that most cases of low pressure have a fixable cause, and many of them are fixable without calling anyone.

This guide walks you through a systematic diagnostic process — starting with the simplest checks and working toward the more complex — so you can find the cause and fix it, or at least know exactly what you’re dealing with before picking up the phone.

Step 1: The Diagnostic Checklist

Work through these in order before doing anything else. A surprising number of low-pressure complaints are resolved at step one or two.

Check Your Main Shutoff Valve

Your home’s main water shutoff valve controls the flow of water from the municipal supply or well into your entire plumbing system. It’s typically located where the water line enters the house — near the water meter, in a basement, utility room, or outside near the foundation.

Main valves come in two types:

• Gate valves (older homes): a round wheel handle that must be turned counterclockwise fully to open. These can be partially closed accidentally during repairs and are notorious for sticking in intermediate positions that restrict flow without appearing closed.
• Ball valves (newer homes): a lever handle that should be parallel to the pipe when fully open.

Check that yours is completely, fully open. Even a quarter-turn from fully open on a gate valve can cause noticeable pressure reduction. This is especially worth checking if you’ve had any plumbing work done recently — contractors sometimes partially close the main valve and don’t fully reopen it.

Test One Fixture vs. Your Whole House

Turn on a tap and assess. Then check a second tap in a different part of the house. This single test tells you a huge amount:

• Low pressure at one fixture only → the problem is local. Start with the aerator or showerhead (see DIY fixes below).
• Low pressure in one area of the house (e.g., only upstairs, or only in the bathroom) → could be a partially closed branch valve, a localized pipe issue, or mineral buildup in older galvanized pipes.
• Low pressure throughout the entire house → the cause is at or before the point where water enters your home: the main valve, the PRV, the municipal supply, a leak, or a whole-house filter.

Check for Leaks

A leak anywhere in your plumbing system diverts water that should be building pressure at your fixtures. Small leaks under sinks or behind walls can cause gradual, whole-house pressure drops that are easy to miss because they happen slowly.

How to check for hidden leaks:

1. Turn off every water-using appliance and fixture in your home.
2. Locate your water meter and note the reading.
3. Don’t use any water for one hour.
4. Check the meter again. If it has moved at all, water is flowing somewhere — and it’s not a tap or appliance you turned on.

Even a slow, dripping leak can consume enough water to noticeably reduce pressure, and a significant leak — in a slab, crawl space, or wall — can cause dramatic drops.

Test with a Pressure Gauge

This is the most informative single diagnostic step and takes about two minutes. A simple threaded pressure gauge — available at any hardware store for under $15 — screws directly onto a standard hose bib (outdoor spigot) or washing machine supply line.

How to use it:

1. Screw the gauge onto the hose bib hand-tight.
2. Make sure no other water is running in the house.
3. Turn the bib on fully.
4. Read the gauge.

What the reading means:

If your reading is below 40 PSI, you have confirmed low pressure and the checklist above narrows down where to look. If it’s in the normal range, the problem may be localized — specific fixtures, a flow-restricted filter, or a partially closed branch valve.

DIY Fixes

Clean Aerators and Showerheads

If low pressure is isolated to one fixture, mineral buildup is the most likely culprit. Calcium and magnesium deposits from hard water gradually clog the tiny mesh screens in faucet aerators and the nozzle holes in showerheads, restricting flow to a fraction of what the fixture is designed to deliver.

For faucet aerators:

1. Unscrew the aerator from the end of the faucet spout (usually by hand; use pliers with a cloth to protect the finish if needed).
2. Disassemble the components — there’s typically a screen, washer, and flow restrictor.
3. Soak in white vinegar for 30–60 minutes, then scrub with an old toothbrush.
4. Rinse and reassemble. If the screen is too far gone, aerator replacements cost under $5.

For showerheads:

1. Remove the showerhead (wrench, with tape on the finish to prevent scratching).
2. Submerge in white vinegar for several hours or overnight.
3. Use a toothpick or toothbrush to clear individual nozzle holes.
4. Reattach and test.

This fix takes under an hour and costs nothing. If it resolves your pressure issue at that fixture, you’re done.

Adjust Your Pressure-Reducing Valve (PRV)

If your home was built after roughly 1990, it almost certainly has a pressure-reducing valve installed on the main supply line where it enters the house. The PRV’s job is to step down the typically higher pressure from the municipal supply (often 80–100+ PSI) to a safe range for residential plumbing.

PRVs are adjustable and they do fail over time — either by drifting to a lower setpoint or by failing in a partially closed position.

To adjust a PRV:

1. Locate the valve on your main supply line — it’s bell-shaped with an adjustment screw or bolt on top, usually with a locknut.
2. Loosen the locknut.
3. Turn the adjustment screw clockwise to increase pressure, counterclockwise to decrease.
4. Make small adjustments (a quarter turn at a time), then recheck with your gauge.
5. Target 50–60 PSI. Re-tighten the locknut.

If adjusting the PRV doesn’t change your pressure reading — or if the valve is visibly corroded or aged — it may need replacement. A plumber can replace a PRV in an hour or two; it’s not a major job, but it does require shutting off the main supply.

The Filtration Connection: A Commonly Overlooked Cause

Here’s a low-pressure cause that most diagnostic guides skip entirely, and yet it’s one of the most common culprits in homes with whole-house filtration: your filter itself.

A Clogged Filter Stage

Every whole-house filter has a sediment pre-filter that catches particles before they reach the main filter media. Over time — especially in homes with iron-rich well water or high turbidity — this pre-filter loads up with debris and begins restricting flow. The result is a gradual, whole-house pressure drop that typically worsens over months until the filter is changed.

If you have a whole-house filter and are experiencing low pressure, check your pre-filter first. For most systems, this is a transparent housing you can visually inspect — a brown or gray pre-filter that was once white is overdue for replacement. Pre-filter cartridges typically cost $5–$15 and should be replaced every 3–6 months depending on your water quality.

A Filter System with Insufficient Flow Rate

This is the more fundamental problem, and it’s one to address before purchasing a filtration system, not after. Every whole-house filter has a rated flow rate in gallons per minute (GPM) — the maximum volume of water it can deliver without creating a pressure drop. If your household’s peak demand exceeds the filter’s rated GPM, you will experience pressure drops during high-use periods, regardless of how clean the filter is.

A typical household’s peak demand — shower running, dishwasher going, a toilet flushing — can easily reach 10–15 GPM. An undersized filter rated for 6–7 GPM will throttle that demand and produce exactly the weak-shower problem described at the top of this article.

This is why flow rate is one of the first specifications to check when evaluating a whole-house filter. The SpringWell CF Whole House Filter delivers 9–20 GPM depending on the system size — high enough that even during peak morning usage, with multiple fixtures running simultaneously, you won’t feel the filter in the line. In hands-on testing, maintaining full pressure under real household load is one of the metrics that separates genuinely well-engineered systems from budget alternatives that look similar on paper.

👉 Read the full SpringWell CF review for detailed flow rate data and how it performs under simultaneous multi-fixture use.

When to Call a Pro

If you’ve worked through the checklist above and still can’t identify the cause of your low pressure, it’s time to bring in a licensed plumber. Specifically, call a professional if:

• Your pressure gauge reads normal but individual fixtures still have low flow — could indicate internal pipe corrosion or blockage, particularly in older homes with galvanized steel pipes that accumulate scale from the inside out over decades.
• Your meter test confirmed a leak but you can’t locate it — slab leaks and in-wall leaks require professional leak detection equipment.
• Your PRV adjustment had no effect — the valve likely needs replacement, which requires shutting off the main supply line.
• You’re on a well and pressure is low — could indicate a failing pressure tank, a worn pump, or a dropping water table, all of which require professional assessment.
• Pressure has dropped suddenly and dramatically — a sudden change (as opposed to a gradual one) often points to a significant leak or a supply line failure that warrants immediate attention.

Low pressure that comes on gradually is usually a filter, buildup, or valve issue. Low pressure that appears suddenly is more likely to be a leak or equipment failure — worth treating as urgent.

The Bottom Line

Most low water pressure problems fall into one of a handful of categories: a valve that’s not fully open, a clogged aerator or showerhead, a drifting PRV, a loaded pre-filter, or an undersized filtration system. Work through the diagnostic checklist in order, fix what you find, and you’ll resolve most cases without a service call.

If the problem persists after checking everything above, you’ve at least eliminated the simple causes and can call a plumber with a clear description of what you’ve already ruled out — which saves time and money on the diagnosis.

👉 See our whole-house filter reviews — all rated for flow rate and tested under real household load conditions.