Low pH well water: blue-green stains, pinhole leaks and the fix
Short answer
Water below pH 6.5 is acidic. EPA's guideline range is 6.5 to 8.5. Acidic water corrodes copper and brass, which leaves blue-green stains and causes pinhole leaks, and can pull lead from older fittings. A calcite neutralizer raises pH for most wells. Very low pH, under about 6, usually needs soda ash injection. Test for lead and copper if your pH is low.
Signs of low pH
- Blue-green stains in sinks and tubs
- Pinhole leaks in copper pipe
- A sour or metallic taste
Treatment options
| pH | Fix | Notes |
|---|---|---|
| 6.0–6.5 | Calcite neutralizer | Dissolves slowly into the water; adds some hardness |
| Under 6.0 | Soda ash injection, or calcite with magnesium oxide blend | Pro sizing recommended |
Neutralize first, then treat iron and manganese. Most iron filters need near-neutral water to work.
Questions well owners ask
Is low pH water safe to drink?
Acidic water itself is mainly a corrosion problem, but it can dissolve lead and copper from plumbing. Test those metals if your pH is low.