How to Read Your City's Water Quality Report

Which report is yours?

The one from the utility named on your water bill. On the Westside that can differ from the city name on your address.

Venice is LADWP, but Marina del Rey next door is LA County Waterworks District No. 29. Culver City is mostly Golden State Water, though LADWP's report also lists Culver City among its communities. Inglewood is split between the City of Inglewood and Golden State Water's Southwest System. Your bill settles it.

Where do you find each Westside utility's report?

On the utility's website, or in the State Water Board's online database, which hosts reports by water system ID.

These are the reports we used for our Westside pages, all covering 2025.

What does the hardness row mean?

It shows how much calcium and magnesium is in the water, expressed as calcium carbonate, as an average for the year and a range from the lowest to highest sample.

Hardness is usually listed in mg/L or ppm, which mean the same thing. Golden State Water also prints grains per gallon and states the conversion: one grain per gallon equals 17.1 mg/L. To convert any report, divide the mg/L figure by 17.1.

Read the average first, then the range. A wide range, like Golden State Water's 137 to 280 mg/L in Culver City, means the water reaching you changes over the year as the source blend shifts. That is a reason to test at your own tap before sizing a softener.

Hardness usually sits in a section for secondary or additional parameters, not with the health-based standards, because there is no health limit for it.

Why do some reports show several hardness numbers?

Because they report each water source separately. Your tap gets a blend, and the report may not say what share comes from each source.

LADWP's report has a column for each source and tells each part of the city which column to read: Western Los Angeles reads the Los Angeles Aqueduct Filtration Plant column. Reading the Weymouth or Diemer columns instead would more than double the hardness figure for a Westside home.

Santa Monica lists its treated local groundwater separately from imported MWD water. Inglewood lists its wells and imported water separately. LA County Waterworks District No. 29 lists two MWD plants and no figure for Marina del Rey itself. Our Westside hardness post puts the right figure for each area side by side.

What else in the report is worth reading?

The water source section, the disinfectant row, and the aesthetic standards for taste, odor and color.

The source section tells you where your water comes from and whether that changes during the year. The disinfectant row tells you whether your utility uses chlorine or chloramine, which matters for which carbon filter will work. The aesthetic standards cover taste, odor, color and dissolved solids, the things people notice day to day.

Reports also list public health goals next to legal limits. A goal is a target set below the limit, and a reading above a goal but below the limit still meets the standard. Every Westside utility in this guide says in its latest report that its water met the health-based drinking water standards.

How do you find a report for any California water system?

Look up the system in the State Water Board's drinking water database, then open its report by system ID and year.

The State Water Resources Control Board's drinking water database lists every public water system with its ID. Reports filed with the state can then be opened at ear.waterboards.ca.gov by system ID and year. Your utility's website is usually the faster route, but the state database is the place to check when a website is out of date.