You turn the handle on your kitchen sink, expecting a strong, steady stream of water, but instead, you get a weak, disappointing trickle. A sudden drop in faucet water pressure is a common and frustrating household problem. It can disrupt everything from washing dishes to taking a shower. While your first instinct might be to call a plumber, the cause is often a simple issue you can diagnose and even fix yourself.
This comprehensive guide will walk you through the most common culprits, from easy DIY fixes to more complex problems that require professional help.
Step 1: Diagnose the Scope of the Problem
Before you start unscrewing pipes, do a little detective work. The location and nature of the low pressure will provide crucial clues to the source of the problem.
- One Faucet or All? Is the low pressure isolated to a single faucet (e.g., just the kitchen sink), or is it affecting every fixture in the house?
- Hot, Cold, or Both? Is the issue only with the hot water, the cold water, or both?
- Check with Neighbors: If the pressure is low throughout your entire house, quickly check with a neighbor. If they are experiencing the same issue, the problem likely lies with the municipal water supply.
Once you have answers to these questions, you can use the following information to pinpoint the cause.
Common Causes for Low Pressure in a Single Faucet
If the problem is isolated to just one faucet, it’s highly likely that the blockage is at the fixture itself. This is often good news, as these are typically the easiest and cheapest problems to fix.
1. A Clogged Aerator
The aerator is the small, screened cap at the very tip of your faucet where the water comes out. Its job is to mix air into the water stream to create a smooth, non-splashing flow. Over time, this screen can become clogged with mineral deposits (scale) and small particles of sediment from the water pipes.
- The Fix: Cleaning the aerator is simple.
- Unscrew the Aerator: Most can be unscrewed by hand. If it’s tight, wrap a cloth around it to protect the finish and use a pair of pliers to gently loosen it.
- Disassemble and Rinse: Take note of the order of the small parts inside (screen, rubber washer, etc.). Rinse all the parts under running water to remove debris.
- Deep Clean: For stubborn mineral buildup, soak the parts in a small bowl of white vinegar for an hour. Use an old toothbrush to gently scrub away any remaining deposits.
- Reassemble and Test: Screw the clean aerator back onto the faucet and test the water flow. This simple fix solves the majority of single-faucet pressure issues.
2. A Clogged Faucet Cartridge
If cleaning the aerator doesn’t work, the next likely culprit is the faucet cartridge. This is the internal valve that controls the flow of hot and cold water when you turn the handle. Like the aerator, small pieces of debris or sediment can get lodged inside it, restricting water flow.
- The Fix: Replacing a cartridge is a bit more involved but is a manageable DIY project for many.
- Turn Off the Water: Use the shut-off valves directly under the sink to turn off the water supply to that faucet.
- Remove the Handle: This usually involves loosening a small set screw.
- Access the Cartridge: Remove any decorative caps and unscrew the retaining nut holding the cartridge in place.
- Pull Out the Cartridge: This may require some gentle wiggling. Take it to a hardware store to ensure you buy an identical replacement.
- Install the New Cartridge: Insert the new cartridge and reassemble the faucet in the reverse order you took it apart.
Common Causes for Low Pressure Throughout the House
If you’re experiencing low pressure in all your faucets, the problem lies further down the plumbing line.
1. Partially Closed Shut-Off Valves
Your home has two important sets of shut-off valves. The main shut-off valve controls the water supply to the entire house, while individual fixtures have their own stop valves (usually under the sink or behind the toilet).
- The Fix: Check that these valves are fully open. The main valve is often located where the water line enters your home (in a basement, crawlspace, or utility closet). The handle should be turned fully counter-clockwise. Sometimes, these valves can be knocked or accidentally turned during unrelated work.
2. A Failing Pressure Regulator
A water pressure regulator is a bell-shaped device installed on the main water line that reduces the high pressure from the municipal supply to a safe level for your home’s plumbing. When one of these devices fails, it can cause a sudden and significant drop in pressure throughout the entire house.
- The Fix: This is a job for a professional plumber. A failing regulator needs to be tested with a pressure gauge and replaced by someone with experience, as improper installation can lead to leaks or damage to your plumbing system.
3. Problems with the Water Heater (Hot Water Only)
If you only have low pressure when you turn on the hot water, the problem is almost certainly related to your water heater. Sediment can build up at the bottom of the tank and clog the outlet pipe, restricting the flow of hot water.
- The Fix: Flushing your water heater can solve this problem and is good routine maintenance. However, if the outlet pipe is significantly clogged or the unit is old, you may need a plumber to inspect or replace the unit.
4. A Hidden Water Leak
A more serious cause of a whole-house pressure drop is a hidden leak somewhere in your plumbing system. A cracked or broken pipe diverts water, meaning less of it reaches your faucets.
- Signs of a Leak: Look for unexplained damp spots on walls or ceilings, a musty odor, the sound of running water when all fixtures are off, or a sudden, unexplained spike in your water bill.
- The Fix: If you suspect a leak, turn off all water-using appliances and check your water meter. If the dial is still moving, you have a leak. Call a plumber immediately to locate and repair it to prevent costly water damage.
When to Call a Professional
While it’s empowering to solve your own plumbing issues, it’s important to know your limits. You should call a licensed plumber if:
- You’ve tried the simple fixes (like cleaning the aerator) without success.
- The problem affects your entire house and isn’t related to the municipal supply.
- You suspect a failing pressure regulator or a hidden water leak.
- You are not comfortable with more advanced tasks like replacing a faucet cartridge or flushing a water heater.
A sudden loss of water pressure can be alarming, but by following a logical process of elimination, you can often identify the cause quickly and restore your water flow to its full, powerful state.