The Short Answer
Your water provider must send you an annual water quality report, often called a Consumer Confidence Report. It names your water source, lists the contaminants found and at what levels, and compares them with the legal limits. Look for the hardness number, which is usually listed in milligrams per liter, and divide by 17.1 to get grains per gallon.
Hardness is not a health issue, but it decides how fast scale builds up in your water heater and fixtures. It is also the number a softener installer needs to size a system.
Why The Report Exists And When It Arrives
Under the Safe Drinking Water Act, administered mainly by the U.S. Environmental Protection Agency, water suppliers must send customers information about drinking water quality every year. The reports are due to customers by July 1 and cover the previous calendar year. They describe where the water comes from, what contaminants are present, and at what levels.
Many providers now post the report online and mail only a notice. If you cannot find yours, call the provider and ask for the latest edition.
Find Your Provider And Your Report
Whittier is served by several providers, so start by confirming which one serves your address.
- Check your water bill. It names the provider, which may be City of Whittier Water, Suburban Water Systems, San Gabriel Valley Water Company, Orchard Dale Water District, or another utility.
- Search the provider's website for 'water quality report' or 'consumer confidence report' and choose the most recent year.
- If your home sits in a system that buys water from others, read the section that lists each source. Some systems blend groundwater with imported water.
- Download the report and keep it with your home records. Compare it year to year for changes.
Terms You Will See In The Report
| Term | What it means | Why it matters |
|---|---|---|
| MCL | Maximum Contaminant Level, the highest level the rules allow in drinking water. | Compare each detected result with it. |
| MCLG | Maximum Contaminant Level Goal, a health-based goal that is not enforceable. | It shows the ideal target, which may be lower than the MCL. |
| ppm or mg/L | Parts per million, equal to milligrams per liter. | Hardness is usually reported in this unit. |
| ppb or ug/L | Parts per billion, equal to micrograms per liter. | One ppm equals one thousand ppb. |
| ND | Not detected. | The lab found none at its detection limit. |
Hardness: Not Regulated, But Useful
The EPA has not set a legal limit for hardness, because the calcium and magnesium that cause it are not toxic. The U.S. Geological Survey uses four bands, measured as calcium carbonate: soft at 0 to 60 mg/L, moderately hard at 61 to 120, hard at 121 to 180, and very hard above 180.
In grains per gallon, those bands run roughly 0 to 3.5, 3.5 to 7, 7 to 10.5, and over 10.5. One grain per gallon equals 17.1 mg/L, so a report that lists 171 mg/L means 10 grains per gallon.
Sections You Will Find In The Report
Layouts differ by provider, but most reports follow the same outline.
Source water
Names the wells, reservoirs, or wholesalers that supply your system and may include a source water assessment.
Detected contaminants
Lists each regulated substance found, the level detected, the legal limit, and the likely source.
Violations and notices
States whether the system met all standards during the year and explains any exceedance.
Health information
Includes required language on lead and other topics for sensitive groups.
Questions To Ask Your Provider
If something in the report is unclear, a call to the provider is free and quick.
- What is the hardness of the water at my address, and does it vary by season?
- Which of the system's sources serves my street at the moment?
- Does the provider offer free or low-cost lead testing or service line information?
- Is there a backflow program for homes with irrigation?
- Where do I report taste, color, or odor problems?
Want Help Reading Your Number?
Call and share your hardness reading. We can talk through what it means for your equipment.
From Report To Decision
Find
Locate the hardness row, often under minerals or general parameters.
Convert
Divide mg/L by 17.1 to get grains per gallon.
Compare
Place the number in the USGS band for your water.
Decide
Use it for softener sizing and tankless flush intervals.
What To Do With The Numbers
A hard or very hard reading explains white crust on faucets, spotty glassware, and a rumbling water heater. It also affects maintenance. Tankless heater makers commonly recommend annual flushing, and hard water areas may need it about every six months.
If you want to treat the water, our page on water softener installation and repair covers sizing from your reading. If your goal is taste or a specific contaminant, water filtration service explains how to match a filter to the report. Owners of tankless heaters can use the number to set a flush schedule.
In La Mirada, Suburban Water Systems operates the local system and blends groundwater from the Main San Gabriel and Central basins with purchased supply, so its report is the one to read there.
What The Report Cannot Tell You
A water quality report describes water as it leaves the treatment plant or wells and enters the distribution system. It cannot see your home's plumbing. Lead, for example, can enter water from old service lines, solder, or fixtures inside a building even when the system meets its standards.
If your home was built long before modern lead limits, or you notice rusty or discolored water, a lab test of your own tap tells you more than the report can. Use a state-certified laboratory and follow its sampling instructions.
Water Quality Report Questions
On your provider's website or by calling its customer service line. The report is due to customers by July 1 each year.
No. The EPA has no standard for hardness because calcium and magnesium are not toxic. Hardness affects scale, soap use, and appliance life.
Divide the milligrams per liter value by 17.1. For example, 171 mg/L equals 10 grains per gallon.
The MCL is the enforceable maximum level allowed in drinking water. The MCLG is a non-enforceable health goal, often lower.
Systems often blend sources. The report describes the system as a whole, and your provider can tell you which mix serves your street.
For health-related concerns, use a state-certified laboratory. For hardness, a simple test strip or your provider's number is enough.