What pH range is considered safe for household water?
Written by
Nguyen Minh
Reviewed by
Prof. Charles Hartman, Ph.D.Proper pH levels, which ensure that infrastructure does not incur damage and that bacterial pollution does not create a serious health risk, to which municipal water must conform (EPA standard: 6.5-8.5 pH), are important to household water safety. Water below pH 6.5 (acidic) tends to corrode plumbing, leach metals, etc., while water above pH 8.5 (alkaline) results in scale deposits. Testing of the pH from time to time is required for greater protection of plumbing systems.
Acidic Water Solutions
- Install acid-neutralizing filters containing calcium carbonate
- Use soda ash injection systems for well water
- Replace copper pipes with PEX to prevent leaching
- Test for lead and copper contamination monthly
- Maintain filters with regular media replacement
Alkaline Water Treatments
- Install acid injection systems lowering pH
- Use reverse osmosis for drinking water points
- Descale fixtures quarterly with vinegar solutions
- Check water hardness levels affecting scaling
- Monitor chlorine levels interacting with high pH
The effectiveness of chlorine disinfection varies with the water's pH. As the pH rises, the effectiveness of chlorine as a disinfectant decreases. Consequently, larger amounts of sanitizer will be required. Residual chlorine should therefore be tested when the pH is above 7.8. This can help minimize bacterial growth without excessive use of chemicals that cause taste and odor problems.
Regional differences greatly influence water chemistry. In a granite area, well water is typically acidic, while in limestone areas, the water is often alkaline. Municipal treatments change the pH in different ways. Your local supply should be tested every three months, as seasonal changes can affect the source supplies.
Health issues go beyond plumbing. Water with a pH level of less than 6.5 is likely unsafe due to the presence of lead or copper. A high pH limits the assimilation of minerals. Use approved testing kits specifically designed for potable water, not those intended for agricultural or swimming pool use.
Take corrective action when testing shows a consistent imbalance. Acid-neutralizing filters will brighten up low pH and are the safest solution. For high pH levels, acid injection systems may be a suitable consideration. Retest the water after 48 hours once corrective action is taken. Make a note of your test results so you can see a trend towards improvement over multiple tests.
Read the full article: Essential Guide to pH Testing Kits for Accuracy
