Swimming Pool Blog

Why is my Pool Water Cloudy?

30 Causes of Cloudy Pool Water
by Mark Garcia June 20, 2014

30 Causes of Cloudy Pool Water

causes of cloudy pool waterCloudy pool water can be a combination of things, and in fact, there is usually more than just one underlying cause.

As we've said for years on this blog, the combination of sanitation, filtration and circulation is the way to clean and clear pool water. Fair enough statement, if you assume that sanitation also means water balance.

Even though you may have finely tuned and balanced water, and your sanitation, filtration and circulation is spot on, you can still develop cloudy water - for a variety of reasons, but affecting one or more of these 3 areas.

To put it another way, cloudy water is the result of your filter and sanitizer being unable to remove very small particulate matter as fast as it's being produced.

Equipment Causes of Cloudy Pool Water
  1. Old pool filter media - sand, cartridge or grids need replacement
  2. Clogged or broken pump impeller or basket, or a pipe blockage - main drain or skimmer
  3. Not running pool filter long enough each day, I recommend 12-18 hrs daily
  4. Stuck skimmer weirs, bringing air into pump
  5. Air leaks in front of pump, bringing air into pump
  6. Damaged pool filter causing water to bypass or get around the filter media
  7. Damaged backwash valve allowing water to recirculate back to pool
  8. Pool pump is too large for pool filter, resulting in ineffective filtering
  9. Closed or broken skimmer or main drain valves
  10. Poor pool return circulation, restricted by pool cleaner, plug or closed valve
Chemical Causes of Cloudy Pool Water
  1. High alkalinity or calcium hardness levels
  2. High cyanuric acid (stabilizer) levels
  3. Dust from recent shock treatment
  4. High pH levels
  5. High mineral or metals content in water
  6. Overdosing with clarifier or stain & scale chemicals
  7. High levels of phosphates or nitrates in the water
  8. Painted pool 'chalking', due to bad water chemistry
  9. High Total Dissolved Solids levels
  10. Saturation Index is > 0.3, indicating a propensity to scale
Environmental Causes of Cloudy Pool Water
  1. Heavy pollen in the air
  2. Smog or air pollutants
  3. Windblown dust from farming or construction
  4. Heavy rain, small wash-ins
  5. Heavily shaded pools
  6. Bird or waterfowl waste
  7. Too many swimmers at one time
  8. Excessive lotions or tanning oils or hair products
  9. High water temperature
  10. Mulch or soil washing into pool during heavy rain


Remember that it can be more than one thing that causes your sanitizer and filtration to become overwhelmed. Look for all of the contributing factors that are making your pool water cloudy. Clarifiers and flocculents can help when your filter seems to be unable to catch up.


Thanks for Reading!
Mark Garcia