How We Research Our Guides
Every guide on this site is built from primary documents, mainly water suppliers' annual reports, government agency pages, building code excerpts and maker manuals, and names the source beside each figure it uses.
On this page
Which sources we use
Local water numbers come from each supplier's own consumer confidence report: Palmdale Water District, LA County Waterworks District 40, Quartz Hill Water District, Rosamond CSD, Cal Water and AVEK. Rules and health limits come from the State Water Board, EPA, CDC, USGS, LA County Public Health and the Contractors State License Board. Climate figures come from NOAA's 1991–2020 normals, and water heater life and care from maker pages such as Rheem's and from ENERGY STAR.
How we handle water report numbers
Each figure is tied to the system, the region and the data year, for example "District 40, Regions 4 and 34, 2026 report, 2025 data." When a supplier posts a newer edition, the newer figures replace the old ones rather than sitting beside them. Hardness is given in mg/L as calcium carbonate with grains per gallon beside it, and rated on the USGS scale rather than a supplier's or store's own wording. Where a printed value is unclear, such as a misprinted average, the page quotes only the range the report prints. Results below a legal limit are described as below that limit; when a supplier reports a violation or an exceedance, the page uses that supplier's own words.
How we report costs
A price appears only when a primary source publishes it, such as the State Water Board's estimate for basic well sampling, or when it is a store's listed price on a stated date. Where no such figure exists, a cost guide sets out the factors behind the bill and the line items worth asking a contractor to put in writing. Contractor blogs and cost-survey websites are not used as sources.
What we leave out
The guides do not test water, products or equipment, and they do not claim to. They leave out forum posts, reader stories, news summaries, water-rating websites and health claims that go beyond the agencies. Product descriptions from SoftPro Water Systems, the store that shares this site's ownership, are reported as the store's own claims; the ownership disclosure explains which pages link to it.
How corrections work
Pages are checked against their sources when they are written and again when a supplier or agency publishes something newer, and the date in each byline changes when a page is revised. A figure found to be wrong is replaced with the corrected source figure. The about page explains who runs the site, and the guides page lists every topic.
More help: see our Antelope Valley water, wells and septic guide.