Civil Code § 798.40 is the Mobilehome Residency Law's core utility-billing statute. It requires three things of any community that bills residents for utilities through a master-meter and submeter system: every bill must separately state the charges and show the meter readings; any third-party billing company must be disclosed on every bill; and for water service — which the statute defines to include sewer, stormwater, and flood control — residents may be billed only their share of the purveyor's actual charges plus a tightly capped administrative fee. Nothing else.
Subdivision (a): Separate Statement, Meter Readings, Rate Schedule Access
Where management provides master-meter and submeter service, each billing period the utility charges must be separately stated and the meter readings shown. Management must also post the specific current residential utility rate schedule conspicuously, or provide the internet website address of that schedule, with free copies available on request. The website-address alternative is current law — physical posting is not the only compliant path.
Subdivision (b): Billing-Agent Disclosure
If a third-party billing agent or company prepares the utility billing, management must disclose on each resident's billing the name, address, and telephone number of the billing agent. Per-bill, not once at onboarding. When Sentinel generates bills on behalf of a community, this disclosure appears on every bill as a matter of course.
Subdivision (c): The Water-Service Regime
Operative January 1, 2022 under AB 1061, and extended to every water purveyor — including municipal and district providers and CPUC-jurisdictional systems — by AB 604 effective January 1, 2024. Where management separately bills water service through submeters, it “shall only bill”:
- (c)(1) Volumetric usage, by a statutory method: proportional to the purveyor's billed usage; or — where the purveyor uses tiered rates — each tier's volume divided equally among the spaces and charged at that tier's rate; or per-space rates where the purveyor charges per space. Hard exclusion: water used by common areas or other persons or entities may never be included in a resident's volumetric charge.
- (c)(2) Fixed charges, allocated either proportionally to each resident's volumetric percentage or divided equally among all spaces.
- (c)(3) One administrative fee — management's and the billing agent's fees combined — capped at the lesser of $4.75 (a base amount management may adjust each calendar year, no higher than the California CPI increase determined by the Department of Finance, from a January 1, 2022 base) or 25% of the resident's (c)(1) usage charge. Use the water-fee-cap calculator to compute the cap for any bill.
Subdivision (d): “Water Service” Is a Bundle
The statute defines “water service” to include water, sewer, stormwater, and flood-control charges. This is why the subdivision (c) limits — including the fee cap — reach a bundled water/sewer bill, not water alone.
Subdivision (f): The CPUC Loophole Is Closed
The subdivision (c) limits apply to all separately billed water service, including where the water purveyor or the community itself is subject to Public Utilities Commission jurisdiction. A regulated purveyor upstream does not lift the caps.
What Compliant Billing Looks Like
Every resident's water bill shows: opening and closing submeter reads with consumption; a volumetric line computed by a (c)(1) statutory method, traceable to the purveyor's actual bill for the same period; a fixed-charge line allocated proportionally or equally; at most one administrative fee, at or under the (c)(3) cap; zero common-area water; and — if a billing agent is used — the agent's name, address, and phone number. Charges that don't trace to the purveyor's bill, second “service fees,” or silent common-area allocations are the classic resident complaints.
Frequently Asked Questions
How much can a mobile home park charge for water in California?
Under Cal. Civ. Code § 798.40(c), a California manufactured housing community that submeters water may bill a resident only three things: their proportional share of the water purveyor's volumetric charges (never including common-area usage), a proportional or equal share of the purveyor's fixed charges, and an administrative fee capped at the lesser of $4.75 (a base amount the statute allows management to adjust annually by California CPI) or 25% of the resident's usage charge. Nothing else may be billed for water service.
Can a mobile home park add a service fee to the water bill?
Only one administrative fee, within the § 798.40(c)(3) cap: the lesser of the CPI-adjustable $4.75 base or 25% of the resident's usage charge — and that cap covers management's and the billing company's fees combined, not each.
Does § 798.40(c) apply to sewer charges too?
Yes. § 798.40(d) defines 'water service' to include water, sewer, stormwater, and flood-control charges, so the subdivision (c) billing limits and the administrative fee cap apply to all of them.
Do the water billing limits apply if the water company is regulated by the CPUC?
Yes. AB 604 (operative January 1, 2024) extended § 798.40's limits to apply even where the water purveyor or the community is subject to Public Utilities Commission jurisdiction (§ 798.40(f)).
What has to appear on a California manufactured housing utility bill under § 798.40?
The utility charges separately stated with the meter readings for the period (§ 798.40(a)), and — if a third-party billing agent prepares the billing — the agent's name, address, and telephone number on each bill (§ 798.40(b)). The current residential utility rate schedule must be posted conspicuously or its internet address provided, with free copies on request.
This page explains the statute in plain English for operators; it is not legal advice. Statutory text verified against the official California Legislative Information site, August 2026.