When Should You Replace Your Pool Water?

While regular maintenance keeps your pool water clean, over time, chemicals, minerals, and contaminants can build up, making it necessary to replace the water. Here are some signs that indicate it’s time for a drain and refill:

1. Water Age

• If your pool water is older than 4–5 years, a full or partial drain may be needed to refresh it.

  
  

2. High Total Dissolved Solids (TDS)

• TDS builds up from chemicals, dirt, and debris over time, making chlorine less effective and causing cloudy water.

• If TDS levels exceed 2,000–2,500 ppm, consider replacing the water.

  
  

3. Persistent Algae Problems

• If algae keep returning even after thorough cleaning and chemical treatment, the water may be too saturated with phosphates and contaminants.

  
  

4. Hard Water & Scale Buildup

• High calcium hardness (above 400 ppm) can cause scaling on pool surfaces and equipment.

• Replacing water can help lower calcium levels.

  
  

5. Chemical Imbalance Issues

• If it becomes difficult to maintain proper pH, alkalinity, or chlorine levels, a water change may be needed to restore balance.

6. Stains & Discoloration

• Stubborn stains or murky water that doesn’t clear up with cleaning could mean the water needs to be refreshed.

Full vs. Partial Drain?

• Full Drain: Needed when TDS or calcium hardness is extremely high.

• Partial Drain: If water quality is declining but not critical, replacing a portion of the water can help.