Thousand Oaks, California
City of Thousand Oaks 2026 Water Quality Report (2025 data), PWSID 5610020. Three labeled hardness columns — MWD Jensen 140 ppm, Calleguas LBWFP 164 ppm, Las Posas 146 ppm. Chloramine residual 1.64 ppm RAA. No Measure S-style residential softener ban turned up — check the sewer agency on the bill.
- Hardness (MWD Jensen)140 ppm (range 137–142)
- Hardness (Calleguas LBWFP)164 ppm (range 161–169)
- Chloramine1.64 ppm RAA (range 1.32–2.05)
- TTHMs17.3 ppb LRAA (range 13–22)
Best match for Thousand Oaks
Salt-based water softener — confirm the district first
Check the sanitation district before installing a salt system.
Ask the agency on the sewer side of the bill before you cut a brine drain. California lets districts restrict self-regenerating units. A “banned in California” blog is not your district.
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Other options that still fit
Salt-free conditioner
A salt-free conditioner changes how scale sticks. It does not soften. Soap and spots stay closer to untreated. No brine line.
Whole-house catalytic carbon for chloramine
Catalytic carbon with a chloramine claim (NSF/ANSI 42 for chloramine). Regular chlorine carbon is the wrong box.
Under-sink reverse osmosis
The under-sink RO we actually run is Cloud RO — NSF/ANSI 58, kitchen tap, not a whole-house tank. Check the exact listing if PFAS is why you are shopping. Shop Amazon first for under-sink RO, or buy Cloud direct. Waterdrop is a tankless option if you want that path. A certifier-listed pitcher is the cheap first step. Nobody is paying for a medical claim.
Shop under-sink reverse osmosisBuy Cloud RO directShop Waterdrop reverse osmosisShop PFAS-listed pitchers
Test the tap first
A homeowner kit is a start. It is not a state-certified lab. Use a certified lab when the decision is expensive.
On the report
- Water utility
- City of Thousand Oaks Public Works — Water Agency
- Hardness
- Additional Parameters table, 2025, three labeled source columns. MWD Jensen Plant (94% of supply) total hardness average 140 ppm (range 137–142). Calleguas LBWFP (5%) average 164 ppm (161–169). Calleguas Las Posas Wellfield (1%) average 146 ppm (145–147). Report also prints 137 ppm = 8.01 gpg and 169 ppm = 9.88 gpg. Those are source columns — not a blended citywide number. — City of Thousand Oaks 2026 Water Quality Report
- Disinfectant
- Total chlorine residual 1.32–2.05 ppm, highest RAA 1.64 ppm, MRDL 4 / MRDLG 4. Footnote [g] says that residual measures chloramines (5 parts chlorine and 1 part ammonia) added system-wide. PWSID 5610020. — City of Thousand Oaks 2026 Water Quality Report
- Brine / salt to the sewer
- Check the sanitation district before installing. No City of Thousand Oaks residential self-regenerating softener ban like LACSD Measure S turned up. That is not a statewide ban finding. Ask Public Works or the agency on the sewer bill before you cut a brine drain.
Also around here
Extra context besides the utility report and the chart above — geology, an unregulated table, or a published study. Not a second set of printed tap numbers.
- MicroplasticsWHO’s 2019 review examined studies that found microplastic particles in treated tap and bottled water in many places. That is a published-occurrence finding, not a number from this city’s water-quality report, and we do not invent a particles-per-liter count for the tap.Microplastics in drinking-water — World Health Organization
- HAA5Same 2025 distribution table. HAA5 highest LRAA 4.5 ppb (range 1.7–5.9).4.5 ppb highest LRAA (1.7–5.9).2026 Water Quality Report (2025 data) — City of Thousand Oaks Public Works
Thousand Oaks city-system drinking water is City of Thousand Oaks Public Works, PWSID 5610020. About 94% MWD Jensen, 5% Calleguas LBWFP, 1% Las Posas wells. Parts of the city are served by California American Water or California Water Service — those are other PWS files. No Measure S-style residential self-regenerating install ban turned up. Ask the agency on the sewer bill before you cut a brine drain. This is not a legal opinion.
The 2026 report prints total hardness 140 ppm (137–142) on Jensen, 164 ppm (161–169) on LBWFP, and 146 ppm (145–147) on Las Posas. We do not blend those columns. Chloramine residual 1.64 ppm RAA (1.32–2.05). TTHMs 17.3 ppb highest LRAA (13–22). HAA5 4.5 ppb (1.7–5.9). Kitchen shopping stays the Cloud RO / Waterdrop path already used on other cities if a listing is why you are looking.
Sources
- 2026 Water Quality Report (2025 data) — City of Thousand Oaks Public Works. Accessed 2026-09-10.
Updated September 10, 2026. A city file is chemistry we can cite plus the sewer rule. No invented detections.