The § 798.40(c)(3) Water
Fee Cap Calculator
California caps the administrative fee a manufactured housing community may add to a submetered water bill: the lesser of the $4.75 statutory base amount or 25% of the resident's usage charge. Enter the usage charge; get the maximum lawful fee.
The amount billed for measured usage under § 798.40(c)(1) only — not fixed charges, and not the fee itself.
Maximum lawful administrative fee — Civ. Code § 798.40(c)(3)
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The statute permits management to adjust the $4.75 base each calendar year, no higher than California CPI (Department of Finance, fiscal-year average), from a January 1, 2022 base. Because that adjustment is computed and documented by each community's management — no agency publishes an operative figure — this calculator uses the unadjusted statutory base. An operator-adopted, documented CPI adjustment may lawfully raise the flat prong above $4.75. This tool is informational, not legal advice.
The Rules Behind the Number
- One combined fee. The cap covers management's and the billing agent's fees together. Stacking a water fee plus a sewer fee on one bill is not supported by the statute — § 798.40(d) defines “water service” as one bundle including sewer, stormwater, and flood control.
- The basis is usage only. The 25% prong is computed on the § 798.40(c)(1) volumetric charge — never on fixed charges, and never on the fee itself.
- The cap applies regardless of the purveyor. Since AB 604 (January 1, 2024), the limits bind even where the water purveyor or the community is CPUC-jurisdictional (§ 798.40(f)).
- The fee cap does not legitimize the billing method. § 798.40(c) permits only its enumerated, usage-based billing methods for submetered water. If the underlying allocation isn't statutory, a compliant fee doesn't fix it — see RUBS vs. submetering.
The full statute walkthrough is at Civil Code § 798.40, explained. Sentinel's compliance engine enforces this cap — and the rest of the fourteen California rules — on every bill before it issues.
Frequently Asked Questions
How much can a California mobile home park charge as a water billing fee?
Under Cal. Civ. Code § 798.40(c)(3), the administrative fee on a submetered water bill is capped at the lesser of $4.75 (the statutory base amount, which management may adjust annually by California CPI from a January 1, 2022 base) or 25% of the resident's volumetric usage charge. The cap covers management's and any billing company's fees combined — one fee, not one each.
Does the water fee cap include sewer?
Yes. § 798.40(d) defines 'water service' to include water, sewer, stormwater, and flood-control charges, so one combined cap applies to the water-service bill — not a separate $4.75 fee per service.
Is the $4.75 amount adjusted for inflation?
The statute permits management to adjust the base amount each calendar year, no higher than the California CPI increase (Department of Finance, fiscal-year average), from a January 1, 2022 base. The adjustment is performed by each community's management — no agency publishes an operative adjusted figure. An operator who has not adopted and documented an adjustment is entitled only to the $4.75 base.
What counts as the usage charge for the 25% calculation?
Only the volumetric amount billed under § 798.40(c)(1) — the charge for measured water usage. Fixed charges allocated under (c)(2) are excluded from the basis, and so is the fee itself.
Want Every Bill Checked Automatically?
This calculator checks one fee on one bill. Sentinel checks fourteen California rules on every bill, every cycle, with the result documented.
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