Before you buy a softener or a filter, it pays to know what is in your water. In San Jose, much of that work has already been done for you by your water company. Here is what to read, what to test and how.
Start with the report you already have
If your home is on city water, your water company tests it and publishes the results in an annual water quality report. Your bill names the company. San Jose Water’s 2025 report covers its main system and the City of Cupertino system, and gives results for each of its sources: mountain surface water, groundwater and Valley Water treated surface water. It includes a map of which source feeds which area.
For hardness, the report alone may answer your question. San Jose Water’s 2025 averages are about 5.8 grains per gallon for Valley Water treated surface water, 9 for mountain surface water and 16.8 for groundwater, with groundwater ranging from 10.2 to 26.4. If another company supplies you, ask your water provider for its annual water quality report.
When a test at your tap makes sense
A water report describes what the provider delivers. Between the main and your glass are your own service line, pipes and fixtures, and any treatment you already have. A test at your tap shows what actually reaches you. It is worth doing when:
- You are about to size a softener and want today’s hardness at your own faucet.
- You notice a taste, smell, color or staining you cannot explain.
- You want to check what an existing softener or filter is doing, before and after it.
- You are choosing a filter for a specific contaminant and want a starting point.
- Your home is on a private well.
Use a state-certified laboratory
For results you can rely on, EPA advises using only laboratories that are certified to do drinking water testing, and CDC advises using a state-certified laboratory. Follow the lab’s instructions for collecting the sample: which tap, which bottle, and whether to run the water first. A quick test at home can give a rough hardness reading, but a certified lab result is what to use when the stakes are higher.
What to ask the lab to test
Choosing home treatment starts with the question that also shapes a test: what contaminant do you want to remove or reduce? Test for that. Tests people ask for, and why:
| Test | Why you might ask for it |
|---|---|
| Hardness | To size and set a softener (USGS: over 180 mg/L is very hard) |
| Total dissolved solids | EPA’s secondary guideline is 500 mg/L, for taste, deposits and staining |
| Iron and manganese | EPA guidelines of 0.3 and 0.05 mg/L, for color, staining and metallic taste |
| pH | EPA’s guideline range is 6.5 to 8.5 |
| Total coliform bacteria and nitrates | What EPA and CDC advise private well owners to test each year |
EPA’s secondary standards are non-mandatory guidelines for aesthetic considerations such as taste, color and odor, and EPA does not enforce them. They are a useful yardstick when you read a result.
If your home is on a private well
A private well has no company report. EPA says private well owners are responsible for the safety of their water, and that private wells are not regulated under the federal Safe Drinking Water Act. EPA and CDC advise testing at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH. CDC adds: test more often if there are problems nearby, after replacing or repairing any part of the well, or if the water’s taste, color or smell changes.
Reading the results against what you want to buy
Results turn a vague worry into a specific question. Hardness points to a softener; see water softener installation in San Jose. A named contaminant points to a filter or system certified to reduce it under the right NSF/ANSI standard; water filtration in San Jose lists them. For treatment at one tap, see reverse osmosis in San Jose. Hardness itself is not a health issue: San Jose Water says hard water does not pose a health risk.
When you ask for a quote, share the result. A good quote names the figure the system was sized or chosen for.
Water Softener San Jose is an independent referral service, not an installer, plumber or laboratory. When you send the form, your details are passed to an independent local water treatment pro, who can contact you and prepare a quote.
Questions people ask
Where can I get my water tested in San Jose?
Use a state-certified laboratory, as CDC advises. Start by reading your water provider’s annual water quality report, which may already answer your question.
What should I test my water for before buying a softener?
Hardness, so the softener can be sized and set for your water. Your provider’s report gives a figure; a test at your tap gives today’s.
How often should a private well be tested?
EPA and CDC advise at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH, and more often after problems, repairs or changes in the water.