Low Water Pressure In The House? Here's What's Wrong And How To ...

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Low household water pressure is more than just frustrating. Showers turn into weak drizzles, washing machines take forever to fill, and faucets barely produce enough flow to rinse a dish. Though it might seem like a minor nuisance, low water pressure can point to anything from a simple clog to a larger plumbing issue.

The key is figuring out whether the problem is isolated to one fixture or affecting your entire home. “Residential homes should have water pressure somewhere between 40 and 80 PSI [pounds per square inch],” says Josh Leclair, owner of Village Home Services in Lowell, Massachusetts. If your water flow feels consistently weak, something might be restricting it. Below, we break down the most common causes of low water pressure in a house, and what you can do to fix them before calling a plumber.

10 Causes of Low Water Pressure

Low water pressure can stem from issues inside your home, outside in the municipal system, or even at a single fixture. The key to narrowing down the cause is determining whether the problem affects one faucet or the entire house, and whether your neighbors are experiencing it too. Below are the most common causes, along with practical steps to address each one.

1. There’s a problem with your water supplier.

If low water pressure is affecting your entire home, the issue might not be inside your plumbing at all. Municipal water systems can experience temporary drops in pressure due to maintenance work, main breaks, firefighting efforts, or unusually high neighborhood demand. Homes located at higher elevations or at the end of a water line might also experience weaker flow during peak usage times.

Before assuming the problem is yours to fix, check with neighbors to see if they’re experiencing the same issue. You can also look for local utility alerts or community app discussions about water service disruptions. In many cases, pressure returns to normal once repairs or high-demand periods pass.

2. Your city recently updated water pressure regulations.

In some areas, municipal water suppliers adjust system pressure to meet updated infrastructure standards, reduce strain on aging pipes, or conserve water during drought conditions. If you’ve noticed a steady drop in pressure, especially after moving into a new home, it’s possible the city’s baseline pressure is simply lower than you’re used to.

Before assuming there’s a plumbing problem inside your home, contact your local water utility and ask what the normal supply pressure is for your area. You can also check your home’s pressure yourself using an inexpensive gauge that screws onto a hose bib. 

Remember: Residential water pressure should typically fall between 40 and 80 PSI, according to Leclair.

If your incoming municipal pressure is consistently on the low end and your plumbing system is in good condition, installing a water pressure booster might be a viable long-term solution. A licensed plumber can confirm whether your supply pressure is adequate and determine if a booster pump is appropriate for your home.

3. Your pressure-reducing valve is failing.

If your neighbors have strong water pressure but you don’t, the issue might be your pressure-reducing valve (PRV). This device regulates the force of water entering your home from the municipal supply. City water pressure often is higher than household plumbing can safely handle,so a properly functioning PRV keeps it within a safe range.

When a pressure regulator begins to fail, you might notice consistently low pressure throughout the entire house, sudden fluctuations, or pressure that starts strong and then drops off. “When a pressure regulator starts to fail, one of the most common signs is inconsistent pressure,” says Leclair.

The most reliable way to diagnose the issue is with a pressure gauge attached to a hose bib. If the reading falls below the typical 40 to 80 PSI range, or fluctuates significantly while water is running, the regulator may need adjustment or replacement. Because improper adjustments can damage plumbing fixtures, this is usually a job best left to a licensed plumber.

4. Your main water shut-off valve isn’t fully open.

Sometimes the fix is surprisingly simple. If your home recently had plumbing work done—or if you’ve just moved in—the main water shut-off valve might not be fully open. Even a partially closed valve can restrict water flow throughout the entire house.

Locate the main shut-off valve, typically found where the water line enters your home or near the water meter. Make sure it is turned completely counterclockwise (for wheel-style valves) or fully aligned with the pipe (for lever-style valves).

If opening the valve restores strong water pressure, you need take no further action. If not, continue troubleshooting to rule out other potential causes.

5. There’s a leak in the water main.

A sudden drop in water pressure can mean there’s a leak in your main water line (the pipe that carries water from the municipal supply into your house). Because this line feeds the entire plumbing system, any break or crack can reduce pressure significantly throughout the home.

Start by checking where the main line enters your house, typically in a basement, crawl space, or garage. Look for pooling water, damp walls, or unexplained moisture. You can also check the ground outside where your water service line runs. If the weather has been dry and you notice a soggy patch of soil, that may indicate an underground leak.

“A sudden change in water pressure is a serious warning sign,” Leclair says. If low pressure appears alongside wet spots, water stains, or the sound of running water when no fixtures are on, contact a plumber right away. Left unaddressed, a main line leak can lead to structural damage, mold growth, and costly repairs.

6. Your pipes are clogged with mineral buildup.

Over time, minerals like calcium and magnesium can accumulate inside your plumbing system, especially if you live in an area with hard water. As that buildup thickens, it narrows the interior diameter of pipes and restricts water flow, reducing pressure throughout the home.

“Buildup is the most common cause of low water pressure in most homes, particularly those serviced with mineral-rich hard water,” Leclair says. In severe cases, he explains, mineral scale can shrink the inside of a pipe to a fraction of its original size.

Fixtures are usually the first place you’ll notice the problem. You can easily clean or replace clogged aerators and shower heads. But if buildup is inside the plumbing lines themselves, a plumber may need to assess whether pipe cleaning, partial replacement, or installing a water softener makes sense to prevent ongoing pressure loss.

7. Your pipes are corroded or outdated.

In older homes, especially those with galvanized steel piping, corrosion can be a major cause of low water pressure. As metal pipes age, rust forms along the interior walls, restricting water flow and increasing the risk of leaks.

Older plumbing systems were also designed for lower household demand. Modern homes often run multiple fixtures at once (showers, dishwashers, washing machines), which can overwhelm aging or undersize piping.

If your home is several decades old and has never had a plumbing update, a licensed plumber can inspect the system and determine whether repiping or targeted pipe replacement is necessary. While more costly than clearing a clog, upgrading old plumbing can dramatically improve both pressure and long-term reliability.

8. There’s a hidden plumbing leak.

Not all leaks are dramatic bursts or visible puddles. A small, hidden leak inside a wall, ceiling, or slab foundation can quietly reduce water pressure by diverting flow before it ever reaches your fixtures.

If you suspect a leak but don’t see obvious water damage, check your water meter. Turn off all faucets and appliances that use water, then monitor the meter. If it continues to move, water might be escaping somewhere in the system. Another red flag is low pressure combined with unexplained increases in your water bill.

Leclair says most whole-house pressure issues originate inside the home rather than with the municipal supply. If you suspect a hidden leak, it’s best to call a licensed plumber right away. Left untreated, even a slow leak can lead to mold growth, structural damage, and costly repairs.

9 .You share a water line with neighbors.

In some older neighborhoods or multi-unit properties, homes might share a single water service line before it branches into individual houses. When that happens, water pressure can fluctuate depending on how much water your neighbors are using at any given time.

If your shower sputters every time the next door neighbors run their sprinkler system or washing machine, shared infrastructure might be the cause. Homes located at the end of a shared line can feel pressure drops more noticeably, especially during peak morning and evening usage hours.

This isn’t typically a quick DIY fix. A plumber can determine whether your home has a shared line and measure incoming pressure. If shared supply is the issue, possible solutions might include installing a water pressure booster or, in some cases, upgrading to a dedicated service line. The latter can be a larger project requiring coordination with your local water utility.

10. There’s an issue with a plumbing fixture.

If low water pressure is limited to one sink, shower, or appliance, the problem is likely localized rather than system-wide. In many cases, the fix is simple and inexpensive.

Common fixture-related causes include:

• Clogged faucet aerators: Mineral deposits and debris can block the small screen at the tip of a faucet. Unscrewing and cleaning the aerator often restores full flow.
• Mineral buildup in shower heads: Hard water can clog spray nozzles over time. Soaking the showerhead in vinegar may dissolve scale and improve pressure.
• Blocked appliance inlet screens: Washing machines and dishwashers have small filters that can become clogged with sediment. Cleaning or replacing them can resolve slow fill times.
• Water heater sediment buildup: If only your hot water pressure is weak, sediment accumulation inside the water heater might be restricting flow.

Checking multiple fixtures throughout the home is the easiest way to determine whether you’re dealing with a localized clog or a whole-house pressure issue, Leclair says. If only one fixture is affected, start there before investigating larger plumbing components.

Ways to Increase Water Pressure

The right fix depends on what’s causing the pressure drop, but you can often narrow it down quickly with a few simple checks. Start with the easiest, lowest-cost steps first, then move toward repairs or upgrades if the problem is widespread or persistent.

1. Confirm whether it’s one fixture or the entire house.

Turn on several fixtures in different areas of the home (a bathroom sink, a shower, and a kitchen faucet), and test both hot and cold water. If only one fixture is weak, you’re likely dealing with a clogged aerator, showerhead, or appliance screen. If everything is weak, focus on main valves, pressure regulation, leaks, or supply issues.

2. Check and fully open the main shut-off valve.

Locate your main shut-off valve, typically where the water line enters the house or near the water meter. Make sure it is fully open. A partially closed valve can restrict flow to the entire home. If your water pressure improves immediately after opening it, you’ve likely found the issue.

3. Clean or replace clogged aerators and shower heads.

If low pressure is isolated to a faucet, unscrew the aerator at the tip and rinse out debris and mineral scale. For shower heads, remove the head and soak it in vinegar to dissolve buildup. This is one of the fastest and most common fixes in homes with hard water.

4. Check appliance inlet screens.

Washing machines (and some dishwashers) have small inlet screens that can trap sediment and restrict flow. If an appliance is filling slowly, check the owner’s manual for how to access and clean the screen, or have a plumber handle it if you’re not comfortable disconnecting water lines.

5. Measure your water pressure with a simple gauge.

If pressure is low across the entire house, a screw-on water pressure gauge can help you stop guessing. Attach it to a hose bib (outdoor spigot) and check the reading with the water fully on. If your reading is consistently below Leclair’s suggested residential water pressure of around 40 to 80 PSI,you likely have a whole-house issue worth investigating.

6. Address mineral buildup or aging pipes.

If your pressure has gradually worsened over time, mineral scale or internal corrosion might be narrowing your pipes. Cleaning fixtures can help at the endpoints, but buildup inside pipes usually requires a plumber to evaluate options such as pipe cleaning, targeted replacements, or installing water treatment (like a softener) to prevent the issue from recurring.

7. Rule out leaks before “boosting” pressure.

It can be tempting to jump straight to a pressure booster, but if low pressure is caused by a leak, boosting can make damage worse. Leclair warns that sudden pressure changes can signal a serious problem. If you notice wet spots, water stains, or a meter that moves when no water is running, call a plumber before making upgrades.

8. Consider a pressure booster only after confirming the cause.

If your municipal supply pressure is consistently low (and your plumbing is in good shape), a booster pump might be a practical long-term solution. This is most common in homes at higher elevations, at the end of a supply line, or in areas where the baseline municipal pressure is simply low. A plumber can confirm incoming pressure and recommend a correctly sized booster system.

FAQ

Q. Why has my water pressure suddenly dropped?

A sudden drop in water pressure is often a sign that something has changed quickly in your plumbing system or local water supply. Common causes include:

• Water main break: A damaged municipal main can reduce pressure throughout your neighborhood until repairs are completed.
• Planned maintenance or hydrant testing: Cities periodically service infrastructure, which can temporarily affect pressure.
• A hidden plumbing leak: A burst or cracked pipe inside your home can divert water before it reaches your fixtures.
• A failing pressure-reducing valve: If your regulator malfunctions, pressure might drop or fluctuate unexpectedly.
• A partially closed shut-off valve: After recent plumbing work, the main valve may not have been reopened fully.

Leclair says never to ignore sudden pressure changes. If the drop is significant or accompanied by wet spots, water stains, or unusual sounds, contact a plumber promptly to rule out a serious issue.

Q. How do you increase water pressure in the shower?

Start by determining whether the issue is isolated to the shower or affects the entire house. If it’s just the shower, remove the shower head and check for mineral buildup. Soaking it in vinegar can dissolve scale and improve flow. You can also remove the flow restrictor (if local codes allow) or replace the shower head with a high-pressure model designed to optimize spray force.

If multiple fixtures throughout the home have weak pressure, the problem likely isn’t the shower head itself. In that case, check your main shut-off valve, measure your home’s water pressure with a gauge, and rule out issues like a failing pressure-reducing valve or hidden leak before replacing fixtures.

Q. Why is my water pressure low in only one bathroom?

If water pressure is low in only one area of the home, it could be an issue of volume. For instance, if the affected bathroom falls at the far end of the supply branch, someone turning on the water in another area of the home could “starve” the pipes for water. In these cases, it’s often a good idea to install pressure-sensitive booster pumps that can supplement the system.

Q. Why is the shower water pressure low when the toilet is flushed?

When a toilet flushes, it pulls a large volume of cold water from your plumbing system to refill the tank. If your pipes are undersized, aging, or partially restricted, that sudden demand can temporarily reduce the amount of water available to other fixtures—like your shower.

In some cases, the issue isn’t just pressure but overall water volume. Older plumbing systems were designed for fewer simultaneous water demands, so running multiple fixtures at once can overwhelm the system. If the pressure drop is minor and brief, it might simply reflect normal system limitations.

However, if the shower nearly shuts off or pressure fluctuates dramatically, it could indicate a larger issue such as mineral buildup, undersized piping, or a failing pressure-reducing valve. A plumber can evaluate whether your system is properly sized and functioning as it should.

Q. Why is my cold water pressure low but hot water pressure is fine?

If only your cold water pressure is weak, the issue is likely isolated to the cold supply line. Common causes include a partially closed shut-off valve, sediment buildup in the cold-water plumbing, or a clogged fixture aerator that’s affecting only the cold side.

In some cases, debris from recent plumbing work or municipal maintenance can temporarily clog cold-water lines or inlet screens. Start by checking multiple fixtures to confirm the problem is limited to cold water. If the issue persists throughout the house, a plumber can inspect the cold-water supply line for blockages or valve issues.

Q. Can a water heater cause low water pressure?

Yes, but typically only on the hot-water side. If your hot water pressure is noticeably weaker than your cold water, sediment buildup inside the water heater might be restricting flow. Over time, minerals can accumulate in the tank and partially block the outlet.

Leclair notes that mineral scale is a common issue in areas with hard water. If sediment is the cause, flushing the water heater may help restore performance. However, if buildup is severe or internal components are failing, professional service or replacement may be necessary.

If both hot and cold water pressure are low, the issue is unlikely to be the water heater and more likely related to valves, piping, or overall supply pressure.

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