Basics · 6 min watch

How to test your tap water at home

San Diego tap water regularly tests at 17 to 20 grains per gallon, which puts it in the very hard category. A five-minute test strip check gives you a directional reading you can act on. It won't replace a professional analysis, but it tells you enough to know whether treatment is worth exploring.

What you'll learn

  • How to use a test strip to check hardness, pH, and chloramine in under five minutes
  • How to read results in grains per gallon and what the San Diego range actually means
  • What the soap-shake test confirms about hardness without any equipment
  • Which contaminants test strips cannot detect at all
  • When to go beyond a DIY test and get a free professional reading

Step by step

  1. Fill a clear glass with cold tap water from your kitchen faucet.
  2. Dip a total-hardness test strip for the time shown on the package, usually one second.
  3. Hold the strip flat and wait 30 to 60 seconds for the color to develop fully.
  4. Match the strip to the chart. Above 10 GPG is hard; above 17 GPG is very hard.
  5. Use a separate chloramine test strip if you want to check disinfectant levels. San Diego water uses chloramine, not free chlorine.
  6. Write down your results and compare them to your utility's annual water quality report for context.
Safety note

Test strips catch hardness and chloramine, but they won't detect PFAS, lead, arsenic, or bacteria. A free in-home water test gives you a full picture in about 30 minutes at no cost.

Rather have a pro handle it?

Water filtration and treatment across San Diego County. A real person picks up, free in-home water test.

Serving San Diego County

Want cleaner water? Book a free in-home water test.

Call for a free water test. No obligation. Most installs start within the week.