Quick Answer:
If pressure was fine at night and every faucet is a weak dribble by morning, first check for hidden or silent leaks, confirm the main shutoff and pressure regulator are where they should be, and read static pressure at an outside hose bib with a pressure gauge. If neighbors have the same problem, report low street pressure to the water utility.
Why This Happens
- Silent leaks that run while you sleep — a leaking toilet flapper, a stuck water softener drain, or an irrigation valve left open — can draw down supply or reduce perceived pressure.
- A failing pressure reducing valve (PRV) or a main shutoff that has slipped toward partly closed can suddenly cut flow to the whole house.
- Low street/main pressure from the utility due to breaks, maintenance, or valve work can make the whole house dribble.
- Air or partial blockages after an outage or repair can make water come back but feel weak until lines are bled.
Step-by-Step What to Do
1. Check the neighborhood
Ask a neighbor or step outside and run a quick tap at a nearby service (if possible). If others have the same problem, contact your city or water utility — the supply may be low or a main may be closed for repairs.
2. Look for silent leaks
Do a quick, quiet check while the house is overall still:
- Toilets: listen for refill sounds or lift the tank lid and press the flapper slightly to see if water keeps flowing into the bowl.
- Water softener: observe the drain line and controller — some units run long regenerations overnight if stuck.
- Irrigation: check the controller and visible zone valves or drip lines for unexpected running water.
3. Verify the main shutoff isn’t slipping
Locate the main shutoff inside or just after the meter. Make sure it is fully open. Gate valves can stick halfway; ball valves should be fully parallel to the pipe. If it appears partially closed, carefully open it fully, but don’t force a stuck valve — that can cause damage.
4. Read static pressure at the hose bib with a gauge
Attach a simple pressure gauge to an outside hose bib (turn the faucet off, screw gauge on, then open the hydrant fully). A normal home static pressure is usually around 40–60 psi; significantly lower readings point to utility supply or meter issues. Take the reading when no other water is running in the house (static).
5. Inspect the PRV (if present)
Find the pressure reducing valve near the main shutoff or meter. Look for signs of leaks, corrosion, or obvious damage. A PRV that fails can suddenly drop downstream pressure. If the PRV has an adjustment screw or nut, note its position but do not adjust it yet unless you have a gauge and know the safe range.
6. Bleed faucets if water comes back but feels weak
If water returns and you hear sputtering, there may be air in the lines. Open the highest and lowest faucets in the house and run until steady water flows. If pressure returns but is still low, see the advice in Water returns but pressure is low and consider checking the PRV or main.
7. If street pressure is low, report it
If your gauge shows low pressure and neighbors confirm the issue, call your water utility. Low mains or hydrant work are common causes and the utility will advise or dispatch crews.
What Not to Do
- Don’t crank the PRV without a gauge—guessing can create dangerous pressure or make it worse.
- Don’t tear apart the water meter or utility-owned equipment yourself — that can be illegal and costly.
- Avoid forcing stuck underground or corroded valves; forcing tools can break the valve and trigger a larger leak.
When to Call a Professional
- Persistent low pressure after you’ve checked for leaks, verified the main shutoff, and read pressure at the hose bib.
- Evidence of a hidden or slab leak (newly wet patches, unexplained higher water bills, or foundation seepage).
- Suspected failed PRV, damaged meter, or anything that requires shutting off the street-side valve or replacing pressure equipment.
- If you’re not comfortable turning valves, working near the meter, or if pipes are frozen or burst.
Safety Notes
- High pressure can damage appliances, fixtures, and hot-water systems—do not increase pressure without a gauge and a clear target pressure.
- If you find a large active leak, shut off the main to protect the home, then call a plumber. Water and electricity together are hazardous—avoid contact with outlets or appliances near pooled water.
- When testing with a gauge, ensure fittings are tight to avoid spray. Wear eye protection if working near valves under pressure.
Common Homeowner Questions
- Q: Could a toilet flapper really drop house pressure overnight?
A: Yes — a toilet running continuously can lower pressure and use a surprising amount of water. - Q: How do I know if the PRV is bad?
A: Signs include consistently low downstream pressure, banging when taps open, or visible leaks at the PRV; confirm with a gauge before replacing. - Q: Water came back but faucets have air and sputter — what now?
A: Open highest and lowest faucets to bleed air; if pressure remains low afterward, further checks are needed and consider the note on Air in all lines after outage.
For more related articles, see the Whole-House Water Supply Interruption hub.