Every other tap in your house works fine. That single fact has already told you most of what you need to know.
If your water pressure is low in one faucet only, the cause is almost always in that fixture or the short run of pipe feeding it. Your main line, your meter, and the rest of your plumbing are working. The faucets that still run strong prove it.
We get this call often in Houston, and most of the time we walk the homeowner through it over the phone. Below we go through the checks in order, starting with the one that costs nothing. Then we cover why this happens more often here, and the signs that mean it is not the faucet at all.
Water reaches each fixture through a branching system. If every other tap works, everything upstream is fine. The restriction has to sit past the last point those lines share. That means the faucet itself or the short pipe feeding it.
The usual causes, easiest to check first:
The aerator is the most common cause and the easiest to rule out.
Checked all five and the flow is still weak? See our Houston plumbing services, or keep reading for what each one looks like.
Two quick tests split this whole problem in half. Both take about a minute.
Test one: run every fixture in the house. Turn on each faucet, tub, and shower. If they are all weak, this is not a single-faucet problem. That points to your main line, a pressure regulator, or the supply coming in, which is a different path entirely. Texas requires public water systems to hold at least 35 psi in their lines, so your utility is worth a call too.
Test two: at the weak faucet, run hot alone, then cold alone. What you find narrows it down fast:
Write down which result you got. Everything below assumes both sides are weak at one faucet, which is the most common version of this.
The aerator is the small screen at the tip of your faucet spout. It mixes air into the stream so the water comes out smooth instead of splashing. It also catches grit, rust flakes, and mineral pieces before they reach your glass.
That is the problem. Over months and years, buildup slowly closes off those tiny holes. The flow drops a little at a time, so you may not notice until it is bad.
Cleaning it takes about ten minutes:
Here is the fastest way to confirm the aerator is your problem. Take it off completely and turn the water on. If the flow comes back strong with the aerator removed, you found your answer.
Look under the sink and you will find two small valves. One feeds hot water to the faucet, the other feeds cold. They control that fixture and nothing else in the house.
A valve that is only partly open restricts the flow at that faucet alone. Turn each one counterclockwise until it stops. That is fully open. Then run the faucet and check.
This happens more often than you would think. Any work done under the sink can leave a valve turned back. So can boxes and cleaning supplies pushed against the handle over time.
One thing to leave alone. If a valve feels stiff, will not turn, or shows moisture around the stem, stop there. Forcing an old valve is how a small problem becomes a wet cabinet.
Inside the body of your faucet is a part called the cartridge. It controls how much water flows and how hot and cold mix together. Minerals and normal wear restrict it over time.
There is a simple way to tell a cartridge problem from a clogged aerator. Watch what the water does in the first few seconds.
| Weak from the start | Starts strong, then fades |
|---|---|
| Points to the aerator | Points to the cartridge |
| Flow is restricted the moment you open the tap | Initial surge, then the stream chokes down |
Trouble setting the temperature points the same direction. If the water is hard to balance and the flow is weak, the cartridge is the likely cause.
Replacing one is not a universal job. Cartridges are specific to the brand and model, and the work means shutting off the supply and opening the faucet body. If the aerator and the valves both checked out, this is where it makes sense to hand it off.orted.
The supply line is the flexible hose running from each shut-off valve up to the faucet. There is one for hot and one for cold. A problem in either one restricts that fixture only.
Start by looking. A sharp bend or a pinch behind stored items cuts the flow without any warning sign. Cabinets get packed, and the hose gets folded against the back wall.
The inside can close up too. Debris knocked loose by work upstream travels and settles in the line. If the hose looks straight and the flow is still weak, the restriction may be inside it.
These hoses have a service life. When one is disconnected for any reason, it is worth replacing rather than reusing.
You cleaned the aerator, opened the valves, and checked the line. If the flow is still weak, or it came back and then faded again, something upstream is doing it.
That is the point where guessing gets expensive. We test the pressure, trace the branch feeding that fixture, and look for what the sink cannot show you.
We have served Houston homeowners since 2003, and our team answers calls 24 hours a day. One weak faucet is rarely urgent. A weak faucet with a second symptom usually is.
We serve Houston and nearby areas including Spring, Humble, Kingwood, Klein, Tomball, Atascocita, Porter, Jersey Village, Conroe, Magnolia, Willowbrook, and The Woodlands.
Abacus Plumbing, Air Conditioning, & Electrical
Business Address: 4001 Kendrick Plaza Dr, Houston, TX 77032
Hours: Open 24 hours, 7 days a week
Call our Houston team: (713) 812-7070
Get directions to our Houston location
Unscrew the aerator from the tip of the spout and soak it in white vinegar for about 30 minutes. Scrub the screen with an old toothbrush, rinse it clear, and screw it back on. Pad your pliers with a cloth if it will not turn by hand.
Low pressure on the hot side alone usually points to your water heater, not the faucet. Sediment settles in the tank and can restrict the hot line leaving it. If more than one fixture has weak hot water, the heater is the likely source..
A strong start that fades points to the faucet cartridge rather than the aerator. A clogged aerator restricts the flow from the moment you open the tap. A worn cartridge passes an initial surge, then chokes down under running pressure.
Yes, water escaping before it reaches your fixtures lowers the pressure you feel. Listen for running water with everything shut off, and watch for a water bill that climbs without a change in use. In Houston, a leak under the slab often shows up this way first.
Not right away. Check the aerator, the shut-off valves, and the supply line first, since those cover most cases. Call when the easy fixes do not hold, the problem spreads to another fixture, or you notice a second symptom like a warm floor spot.
Abacus Plumbing, Air Conditioning & Electrical serves: The Woodlands, Katy Pearland, Spring, Cypress, Sugar Land, Humble, Kingwood, Friendswood, Missouri City, Pasadena and more. View All Service Areas » (please call to confirm service in your area)
Open Including Holidays
ALAN O’NEILL M-20628 | TACLA135747C | TECL 30557
© 2026 Abacus Plumbing, Air Conditioning & Electrical. All Rights Reserved