When water comes out of the tap weakly, slowly, or looking off, the first question is where the trouble starts. In St. Louis, that question matters because a problem on the utility side of your meter is the provider's job, while a problem past the meter is yours to fix or hire out. Here is a plain way to sort it out before you call anyone.
Start with the pattern
Write down exactly what you see. Is the weak flow in every fixture, or only one? Is it on the hot side, the cold side, or both? Does it happen all day, only in the morning, or only when the washing machine runs? Those answers point in different directions.
- Every fixture weak at once usually points to the supply coming into the house, or to a shared valve or regulator.
- One fixture weak usually points to that fixture, such as a clogged aerator or a partly closed shutoff under the sink.
- Hot weak but cold fine points toward the water heater, its inlet valve, or the hot supply line.
- Weak only at peak times can reflect demand on the street main, which some older St. Louis neighborhoods notice on hot summer days.
Run the meter test
Find your water meter. In many St. Louis homes it sits in a basement, a crawl space, or a box near the curb. Shut off every faucet, the icemaker, and any outdoor hose. Then read the dial or register, wait a while without using any water, and read it again. If the reading has moved, water is leaving the system somewhere. Check the toilet flapper and the hose bibs first, since both can leak without leaving obvious stains.
Check the shared parts inside the house
If the meter does not move, the supply is probably reaching the house. Look at the main shutoff valve and the pressure regulator, if your home has one. A regulator that has stuck or was partly closed during an earlier repair can cut flow to the whole house. Adjusting or replacing a regulator is work for a licensed plumber, not a quick homeowner fix. While you are there, confirm the water heater inlet valve is fully open.
Look at the fixture side
Unscrew the aerator at a weak faucet and rinse it. Mineral deposits and small debris clog aerators, and clearing one is a simple task a homeowner can do. If flow returns, the problem was local to that fixture. If flow stays weak with the aerator out, check the shutoff valve under that sink and the faucet cartridge.
Signs the problem is in the drains, not the supply
Weak flow is not the same as a slow drain. If water backs up in a tub when the toilet flushes, or gurgles from a floor drain, the trouble is likely in the drain and vent system or the sewer line. Older clay sewer lines in many St. Louis neighborhoods can crack or collect roots, and that can produce slow drains and backups. A sewage smell from a basement floor drain after heavy rain deserves prompt attention from a licensed plumber.
Check the street side before assuming the worst
Check whether the water utility has posted work nearby or reported a main problem, and ask neighbors whether they see the same thing. Note the date and time, since street repairs and heavy use can cause short dips that clear on their own. Also keep in mind that the pipe between the street main and your meter may be your responsibility, not the utility's. Check your property records or ask the provider who owns the line at your address. If the problem is on the utility side, report it to the provider that serves your address rather than digging on your own.
When to stop testing and call
- The meter keeps moving with every fixture off and you cannot find the leak.
- Water is seeping near the foundation, or the floor or walls stay wet.
- Hot water is weak or drops off suddenly.
- Backups appear in more than one drain at the same time.
Keep a short log with the date, the fixture, what you checked, and the meter reading. A plumber or the utility can work faster with clear notes and a photo of the meter. Treat a fast, clear answer as a starting point, and confirm the next step with a licensed professional before paying for major repairs.