Water Knowledge

Ph

Summary: pH describes how acidic or basic your water is on a scale of 0–14 (7 = neutral). Low pH (acidic) can corrode plumbing and dissolve metals; high pH (basic) can cause scale and flat/“soda” taste. Because pH influences both corrosion and treatment performance, testing is the first step to stable home water.

Why homeowners should care

pH affects everything: metal leaching (lead/copper), scale in heaters and fixtures, soap performance, and how well disinfectants and filters work. If you rely on a private well—or your home has older plumbing—knowing and stabilizing pH protects health and equipment.

What pH really means

  • Low pH (< 7): More corrosive; can pull metals from copper/lead plumbing and cause blue-green stains, bitter/metallic taste, and pinhole leaks.
  • Neutral to slightly basic (≈ 7.0–8.0): Typical for many supplies; good general range for home plumbing.
  • High pH (> 8): Can promote scale when hardness is present and may give a slick or “baking-soda” taste.

Note: pH works together with alkalinity (buffering) and hardness. Low alkalinity makes pH bounce around; hardness + higher pH increases scale.

When to test

  • At move-in or when starting a private well baseline.
  • Annually for private wells; seasonally if your area has big wet/dry swings.
  • After plumbing/well work, new treatment equipment, or signs of corrosion/scale.
  • Any time you’re troubleshooting lead/copper, blue-green stains, or rapid scale.

How we test

HealthWaterLab measures pH with a calibrated laboratory electrode. For corrosion/scale questions we recommend pairing pH with alkalinity, hardness, conductivity/TDS, and (when metals are a concern) lead and copper.

How to collect a good sample

  • Use the kitchen cold-water tap or primary drinking tap.
  • Run water several minutes to bring in fresh water (unless you are intentionally testing first-draw for lead/copper).
  • Fill to the mark; cap immediately. Deliver promptly—pH can shift if water sits open to air.

How to read your result

  • < 6.5: Acidic and potentially corrosive—evaluate copper/lead risk; consider pH correction.
  • 6.5–8.5: Common consumer range. Check alkalinity/hardness to judge stability and scale risk.
  • > 8.5: Tends toward scale with hardness; taste may be flat/soapy—consider adjustments if appliances or aesthetics suffer.

Practical ways to manage pH

  • Raise low pH: Acid-neutralizing calcite filters (calcium carbonate) or calcite–magnesia blends; soda-ash injection for higher demand. Re-check hardness afterward—neutralizers add calcium.
  • Lower high pH: Acid feed (carefully controlled) or blending with lower-pH water. Many homeowners manage scale instead (softening + heater maintenance) rather than lowering pH.
  • Stabilize swings: Increase alkalinity (buffer) and avoid long stagnation. Keep well caps sealed; limit air intrusion that drives off CO2 and shifts pH.
  • Verify: After any change, re-test pH along with alkalinity/hardness and check for lead/copper if corrosion was a concern.

FAQ

What pH is “best” for home plumbing?

Most homes do well around 7.0–8.0 with adequate alkalinity. Very low pH increases corrosion; very high pH plus hardness increases scale.

My water is eating pinholes in copper—will fixing pH help?

Yes. Low pH and low alkalinity are common drivers of copper corrosion. Correcting pH and buffering, plus removing stagnation, usually helps. Replace badly deteriorated sections as needed.

Why did my pH change after installing RO?

RO water has very low mineral content and can read slightly acidic from dissolved CO2. That’s normal at the RO tap and not harmful; many homeowners add a small remineralization cartridge for taste.

Does a softener change pH?

Standard softeners exchange hardness minerals for sodium/potassium and generally do not change pH. They reduce scale by removing hardness.

Should I chase a single pH number or look at other tests too?

Look at the full picture: pH + alkalinity + hardness + TDS/conductivity. Together they predict corrosion/scale better than pH alone.

Is high pH water safe to drink?

At typical household levels it’s generally fine, but taste can be flat/soapy and scale increases when hardness is present. Manage aesthetics and equipment protection as needed.

How often should I test pH?

Annually for private wells; after any treatment changes; and when you see corrosion/scale symptoms or taste shifts.

Can carbon filters fix pH?

No. Carbon improves taste/odor (e.g., chlorine) but doesn’t adjust pH. Use neutralizers or carefully controlled chemical feed to change pH.

What is alkalinity and why does it matter for pH?

Alkalinity is the water’s buffering capacity—how well it resists pH change. Low alkalinity allows pH to swing; moderate alkalinity stabilizes it.

Will raising pH increase hardness?

Neutralizing filters (calcite) add calcium, so hardness typically rises. Many homes pair pH correction with a softener to control scale.

Want help dialing in stable pH? See testing kits and step-by-step guidance at HealthWaterLab.com.