Quick Answer:
Cloudy or milky-looking water right after a pressure-reducing valve (PRV) is installed is most often tiny air bubbles from a change in system pressure. Do a few simple checks — filling a clear glass, comparing hot and cold taps, and inspecting aerators — to confirm. If cloudiness does not clear, leaves a residue, or shows up at several fixtures, call a plumber to test the source safely.
Why This Happens
Installing a PRV changes the water pressure and flow patterns in your pipes. That sudden shift can let dissolved air come out of solution as microscopic bubbles, which make water look cloudy. Less commonly, the disturbance can dislodge mineral deposits, sediment, or bits of fitting material. Air will usually clear from the glass from bottom to top within a minute; solids will not.
If the problem looks confined to a single area, check related fixtures such as the shower — for example, Milky water in shower only. If you notice particles coming from hot taps, that points toward heater or pipe-scale issues — see White particles in hot water.
Step-by-Step What to Do
Step 1 — Fill a clear glass and wait
- Fill a clear glass from the affected tap and set it on a flat surface.
- Watch for about 60 seconds. If the cloudiness rises and the water clears starting from the bottom, that’s trapped air escaping as bubbles.
- If the water stays cloudy or you see material that settles or clings to the glass, that suggests solids or sediment.
Step 2 — Compare hot and cold taps
- Open a cold tap and a hot tap (separately) and observe both with the same glass test.
- Cloudiness only on cold taps usually means air from the supply or PRV adjustment. Cloudiness only on hot taps can point to the water heater or mineral loosened by pressure changes.
Step 3 — Check aerators and shower heads
- Unscrew faucet aerators and inspect for white specks, flakes, or mineral deposits. Clean or rinse them into a paper towel to see what comes out.
- Also look inside shower heads and inline filters for debris. Small white particles in aerators often indicate scale or fitting fragments rather than air.
Step 4 — Run a brief flush (controlled)
- Open a faucet for 30–60 seconds to see whether the water clears; this helps push trapped air out. Do this only once or twice — excessive flushing can stress appliances or waste water.
- After flushing, repeat the clear-glass test to confirm improvement.
What Not to Do
- Don’t assume all cloudiness is harmless air. If you see residue, particles, or persistent cloudiness, don’t ignore it.
- Don’t repeatedly or aggressively flush the water heater trying to “clear” the problem yourself; repeated draining or back-flushing can damage the heater or plumbing.
- Don’t use chemical additives or DIY descalers in the system without professional advice.
If cloudiness persists or leaves residue, have a plumber inspect the system rather than continuing home remedies.
When to Call a Professional
Call a licensed plumber if any of the following apply:
- Cloudiness affects multiple fixtures and does not clear with the glass test.
- You find settling particles, residue, or flakes after water sits or when you filter the water.
- You’re unsure whether the issue is air, minerals, or material from a fitting after doing the basic checks.
A plumber can safely test water pressure, check the PRV, inspect the heater and piping, and run water quality tests to identify contamination or mechanical issues.
Safety Notes
- If water looks cloudy and has a strange odor or color, avoid drinking it until it’s checked.
- Wear gloves when handling aerators or cleaning sediment to avoid contact with unknown particles.
- Do not attempt major repairs to the PRV, heater, or internal valves unless you are qualified; turning valves incorrectly can create unsafe pressure conditions.
Common Homeowner Questions
- Is cloudy water dangerous? — Short answer: Usually not when it’s just air, but persistent cloudiness or particles should be checked.
- How long should cloudiness last after a PRV install? — Expect clearing within minutes to a few hours; persistent issues need inspection.
- Can I fix this myself? — Do the glass test, compare hot/cold, and clean aerators. If the problem stays or you find residue, call a plumber.