Hard Water Softeners & RO in Patterson, CA

If you moved to Patterson from almost anywhere else, the water was probably the first surprise: white crust on the faucets within weeks, glasses that never come out clear, and a water heater that starts popping early. The numbers back that up. Patterson’s 2025 report puts average hardness at 402 ppm (parts per million), very hard water and about twice Modesto’s average.

Patterson’s city water is all groundwater, and chromium-6 occurs naturally in it. The city reports that its wells exceed California’s 10 ppb chromium-6 limit, has an approved compliance plan, and sends quarterly notices while treatment is planned. Under the state rule, a system Patterson’s size isn’t considered in violation until after October 1, 2027.

Just moved from the Bay Area and your skin feels drier? Many people notice it. San Francisco’s water averaged 62 ppm of hardness in 2025, and EBMUD describes its water as soft to moderately hard [SFPUC 2025 Annual Water Quality Report] [EBMUD water quality FAQs]. Valley tap water is often harder, and the chlorine or chloramine (chlorine combined with ammonia) used to disinfect city water can dry out skin and hair. A water softener takes care of the hardness, and whole-house carbon filtration reduces chlorine at every tap.

Chromium-6 in Patterson water: what homeowners should know

What it is. Hexavalent chromium, or chromium-6, is one form of the metal chromium. It occurs naturally in rocks and soil, and it also comes from industry, like electroplating and leather tanning [City of Patterson 2025 Consumer Confidence Report]. The city says the chromium-6 in Patterson’s groundwater is naturally occurring, not the result of industrial activity or pollution [City of Patterson 2025 Consumer Confidence Report].

Patterson’s numbers. The 2025 Consumer Confidence Report lists hexavalent chromium at an average of 18 µg/L (parts per billion), with a range of 4.9 to 39.7 µg/L, for samples taken 2022 to 2025 [City of Patterson 2025 Consumer Confidence Report]. The city’s chromium-6 page says its supply currently averages about 16 to 21 ppb, and the report says all active potable wells in the Lower Aquifer are above the state limit [City of Patterson Chromium-6 page] [City of Patterson 2025 Consumer Confidence Report].

The state limit and timeline. California’s maximum contaminant level for chromium-6 is 10 µg/L, effective October 1, 2024 [State Water Board: Chromium-6]. A system Patterson’s size isn’t considered in violation until after October 1, 2027. The city’s compliance plan was approved January 9, 2026 and maps out a long-term fix by the state’s September 2030 deadline, with quarterly public notices in the meantime [City of Patterson 2025 Consumer Confidence Report] [City of Patterson Chromium-6 page]. The city also says there is no immediate public health emergency [City of Patterson 2025 Consumer Confidence Report].

Why it matters. The concern is long-term exposure. The State Water Board notes that the hexavalent form has been shown to be carcinogenic and toxic to the liver, citing California’s OEHHA, and it’s on the state’s Proposition 65 list of chemicals known to cause cancer [State Water Board: Chromium-6].

What you can do. A water softener doesn’t remove chromium-6. For its own wells, the city’s feasibility study evaluated reduction-coagulation-filtration, ion exchange and reverse osmosis [City of Patterson 2025 Consumer Confidence Report]. For your home, reverse osmosis can reduce chromium-6. According to the California State Water Board, “RO is a mature and viable technology for hexavalent chromium removal.” [California State Water Board, Hexavalent Chromium MCL Initial Statement of Reasons] Ask us about a free water test.

Local water challenges in Patterson

• Very hard water: fast scale on fixtures, glass, kettles and water heaters
• Chromium-6 above the state limit in city groundwater
• Soap and shampoo that won’t lather
• Chlorine taste and odor

How we help Patterson homes

Patterson is softener country. With water this hard, a properly sized water softener is usually the first piece; a salt-free conditioner is still an option if you’d rather skip salt. A softener doesn’t remove chromium-6, though. Under-sink reverse osmosis can reduce chromium-6 (see Chromium-6 in Patterson water above for the State Water Board source). Ask us about a free water test. A whole house water filter handles chlorine taste.

Read next: Chromium-6 in Patterson: plain-English answers for homeowners