Various signs may indicate that it is time to replace your pool filter. Please note that this list is not necessarily conclusive. Filter Age: There are different limits to how long a filter can last. This can vary by filter type and make. Take note of your filter’s use-by date and do not exceed it. Damage to the Filter: When cleaning your pool filter, be sure to inspect it for signs of damage, such as tears in the fabric or damage to the plastic end cap. If your filter has damage, it will need to be replaced, as damage can reduce its ability to help keep your pool clean. Water is in Poor Condition: If your pool water is dirty despite having the right chemical balance, it could be a sign that your pool filter needs to be replaced. Other signs to look for include requiring more sanitizer than normal or needing to run the filter longer to keep your water clean.