Why is my pool water cloudy?
Cloudy pool water usually comes from weak filtration or off-balance chemistry. Test free chlorine, pH and total alkalinity first: a high pH or high alkalinity can cloud water, and chloramines from low free chlorine do the same. Then empty the baskets, run the pump, and clean or backwash the filter when its gauge says so.
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By Kasra Taheri, Founder, LoclisPublished
Researched and drafted with AI, then checked claim by claim against the sources listed below before it was published. Prices and rules change; the dates beside each source say when it was last checked.
Step by step
Read when to stop and call a pro, further down this page, before you start.
Step 1: Test free chlorine and pH
Test with a drop-based kit or good strips, taking the sample from about elbow depth and away from the returns. Virginia's water quality standard for pools is free chlorine of 1.0 to 3.0 ppm and a pH of 7.2 to 7.8.[2]
Step 2: Test total alkalinity
Check total alkalinity as well; the Portsmouth guide gives an acceptable range of 80 to 120 ppm.[1]
Step 3: Empty the skimmer and pump baskets
A full basket restricts flow, and the Portsmouth guide says to clean the skimmer basket out daily.[1]
Step 4: Run the pump long enough
Run the pump continuously until the water clears, since the filter can only clean water that passes through it.
Step 5: Read the filter gauge
Clean or backwash the filter as its manual says when the pressure has risen well above its clean reading; for a rapid sand filter with one gauge, the Portsmouth guide gives 3 to 5 psi above the start-of-cycle reading.[1]
Step 6: Brush and vacuum
Brush the walls and floor, then vacuum slowly so fine dirt goes to the filter and does not drift back up.
Step 7: Correct chemistry in order
Fix chlorine first, then pH, then alkalinity, adding one product at a time as its label directs. Never mix anything with chlorine except water.[1]
Step 8: Shock if the chlorine smells strong
If chloramines are the cause, superchlorinate, which the Portsmouth guide describes as raising free chlorine to 5 to 10 ppm, following the product label.[1]
Step 9: Retest the next day
Recheck the readings and the water after a full day of filtering before adding anything else.
Start with the test kit
Cloudy water has a short list of causes, and a test kit plus a look at the filter finds most of them. Work through chlorine, pH and alkalinity, then the filter and pump, in that order.
Virginia's water quality standard for pools keeps free chlorine between 1.0 and 3.0 ppm and pH between 7.2 and 7.8.[2] It is written for regulated pools, but it is a sensible target for a home pool too.
The chemistry causes
High pH. The effects of a high pH include cloudy pool water, scale on pipes and equipment, slow-acting chlorine and irritated eyes.[1] If pH tests above 7.8, lower it gradually with a pH reducer, following the label.
High alkalinity. The acceptable range for total alkalinity is 80 to 120 ppm, and when it is too high it resists change in pH and can also cause cloudy water.[1] So if pH is hard to move, check alkalinity.
Chloramines. Excessive chloramines may also cause a cloudy, dull appearance to pool water.[1] Chloramines form when chlorine combines with nitrogen-containing substances such as ammonia, which sweat and urine bring into the water.[1] A strong chlorine smell, red eyes and a cloudy pool with a low free chlorine reading point here. The fix is a shock: superchlorination means raising the free chlorine residual to 5 to 10 ppm to burn off chloramines.[1] Use a product made for it and follow its label.
Do the chemistry one product at a time. Never mix anything with chlorine except water,[1] and do not drop tablets, liquid or granular chlorine straight into the pool, return skimmers or gutters to hold daily levels.[1] If you are not sure how to correct a reading, see how to balance pool chemicals.
The filtration causes
Chemistry in range and still cloudy? Suspect the filter. The most common reasons are a pump that does not run long enough, full baskets, a dirty filter or a pool whose water circulates too slowly.
Start with the baskets. The skimmer basket should be cleaned out daily to allow for maximum flow through the skimmer.[1] Then look at the filter gauge. When the water flow through a sand filter becomes too low, it is necessary to clean or backwash the filter,[1] and as a rule of thumb, for a rapid sand filter with only one gauge, backwash when the pressure has risen 3 to 5 psi from its reading at the start of the cycle.[1] A cartridge filter needs its element rinsed or soaked instead; see how to clean a pool cartridge filter. Your filter's own manual overrides these rules of thumb.
Run time matters. The guide gives recommended turnover rates, to provide efficient disinfection and maintain pool water clarity, of 6 hours for a public pool and 8 to 12 hours for a semi-public pool.[1] A home pool pump that runs only a few hours a day, or an undersized pump, may not turn the water over often enough to keep it clear.
How clear is clear enough
A simple test for clarity: Portsmouth's pool code requires the water of an open public pool to be clear enough that a six-inch black-and-white disc on the bottom at the deepest point is clearly visible from the deck at distances up to ten yards.[1] If you can no longer see the main drain clearly from the deck, treat the pool as closed until it clears. Clear water does not necessarily mean that the pool is sanitary,[1] so keep testing chlorine even when the water looks fine.
Stop and call a pro if
- The water stays cloudy for several days after the readings are in range and the filter has been cleaned. That points to a worn filter medium, a cracked part inside the filter, or a circulation fault.
- The pump runs but pulls little water, leaks, or makes a grinding noise. Pump and plumbing repair is a job for a professional.
- Anything electrical or gas is involved: a pool light, an automation panel, a heater or a buzzing motor. Do not open or rewire them yourself.
- The repair would cost $1,000 or more. If the work you are considering is valued at $1,000 or more, a valid Virginia contractor's license is required.[3]
- You are unsure what to add. Ask the supplier who sells the chemicals or hire a service.
Getting help in Virginia
Once the water clears, how to clean a swimming pool and how often to clean your pool keep it that way. If you would rather hand it off, read what a pool service company does each visit. Browse pool and spa services or more pool and spa answers.
When you are ready, describe the problem once and local pool pros quote it.
Common questions
- How long does cloudy pool water take to clear?
- Usually a day or two once the chemistry is right and the pump runs around the clock. If it is no better after two or three days of filtering with the readings in range, the cause is probably the filter or circulation rather than the chemicals.
- Can high pH make a pool cloudy?
- Yes. The Portsmouth Health Department's operator guide lists cloudy water among the effects of a high pH, alongside scale and slower-acting chlorine.
- Is cloudy water the same as green water?
- No. Cloudy water is hazy but still blue or grey, and points to filtration or balance. Green water means algae, which needs chlorine brought back up and heavy brushing; see the guide to cleaning a pool linked below.
- Should I add more chlorine to a cloudy pool?
- Only if the test says free chlorine is low or chloramines are high. Adding chlorine to water that is already in range will not fix a pH, alkalinity or filter problem.
- Is cloudy pool water safe to swim in?
- It is better to stay out. Poor clarity hides the bottom, which is a safety problem in itself, and the guide notes that clear water does not necessarily mean the pool is sanitary, so cloudy water gives you even less to go on.
Sources
- [1] Pool Operation and Maintenance Guide (compiled 2018), Portsmouth Health Department, Virginia Department of Health. Checked October 27, 2026.
- [2] 12VAC5-462-290. Water quality standards, Virginia Administrative Code, Virginia General Assembly. Checked October 27, 2026.
- [3] What You Should Know Before You Hire a Contractor, Virginia Board for Contractors, DPOR. Checked October 27, 2026.
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