Quick Answer:
Cloudy water right after bringing a system back into service is most often trapped air or tiny mineral bubbles. Run water at every sink, tub and hose bib so air and residue are pushed out; if the cloudiness persists, smells, or tastes odd, stop using the water and get help.
Why This Happens
During winterization a home’s plumbing is drained, or air and sometimes antifreeze are pushed through lines. When you refill the system, air pockets and microscopic gas bubbles can stay trapped in pipes and fixtures. Those bubbles make water look milky or cloudy at first. Cold water also holds dissolved gases that form tiny bubbles as pressure and temperature change. In most cases this clears on its own once the air is purged.
Step-by-Step What to Do
1. Turn water back on slowly and check the system
- Open the main shutoff or supply valve slowly to avoid pressure spikes. Listen for obvious leaks as the lines pressurize.
2. Run all fixtures after winterization to purge trapped air
- Open the cold side at each sink, tub, shower, utility sink and outside hose bib. Let each run for several minutes until the flow runs steady and clear.
- Work from the lowest fixtures (basement or main floor) up to upper floors so air is pushed out of the highest points last.
3. Flush the hot side after the water heater is refilled
- Make sure the water heater has refilled and is full per the manufacturer’s instructions, then run hot water at each fixture to remove trapped air from hot lines.
4. Remove and check aerators and shower screens
- Unscrew faucet aerators and shower heads, rinse out debris and run the fixture without the screen to flush any loosened particles. Inspect for sediment or flakes.
- If you see small white particles collecting in the screen, learn how to handle issues like White specks clogging aerators for cleaning and replacement tips.
5. Watch for changes and document what you see
- If the water is cloudy but clears within a minute or so after running, that behavior is common—see notes on Cloudy water that clears after a minute.
- If cloudiness lasts, is colored, or the water tastes or smells off, stop using it until you determine the cause.
What Not to Do
- Do not re-winterize without purging air. Repeating winterization before flushing can trap more air and make the problem worse.
- Do not ignore a persistent smell, taste, or colored water; these can be signs of contamination or antifreeze residue.
- Do not attempt major repairs on pressurized lines without shutting off water and knowing what you’re doing; call a pro if you’re unsure.
When to Call a Professional
- Cloudiness does not clear after running fixtures for several hours or reappears frequently.
- You detect any chemical smell or sweet taste that could indicate antifreeze or other contaminants.
- Visible sediment, colored water, low water pressure after flushing, or leaks appear when the system is pressurized.
Safety Notes
- If you suspect antifreeze contamination, stop drinking the water and use bottled water until a professional confirms it’s safe.
- If you used automotive (ethylene glycol) antifreeze by mistake, treat it as potentially toxic and contact local poison control or a plumber immediately.
- Wear gloves and eye protection when removing aerators or working with fixtures to avoid injury from debris or pressurized sprays.
Common Homeowner Questions
- Why did the water go cloudy after I turned the supply back on? — Trapped air and tiny bubbles are the usual cause after winterization; flushing the lines clears them.
- How long should I run the faucets? — Run each fixture several minutes until flow is steady and clear; higher or longer if you had extensive draining or used compressed air during winterization.
- Is cloudy water dangerous? — Generally no if it clears quickly; if it’s colored, has a smell/taste, or doesn’t clear, stop using it and consult a professional.
For more related articles, see the White Particles, Cloudy Water, or “Milky” Water hub.