RUBS calculator
Split one master-meter water bill across your lots — with a park share held back for common-area use — so the pennies add up to the bill exactly.
How a fair RUBS split works
RUBS (ratio utility billing) is what a master-metered park does instead of submetering: take the utility bill, hold back the park's own share, and divide the rest across occupied lots by a consistent formula. This calculator splits evenly per lot — the simplest formula and the easiest one to defend, as long as it's written into the lease. Two rules keep it fair and keep disputes short:
- Hold back a park share first. The master meter includes water no tenant used — irrigation, the office, a laundry room, leaks in park-owned lines, and vacant lots. Splitting 100% of the bill makes tenants pay for your common areas.
- Show the math on the bill. Total bill, park share, the number of lots, and the per-lot result. A tenant who can re-do the arithmetic is a tenant who doesn't call.
The honest limitation: RUBS can't see who actually used the water, so careful tenants subsidize the running toilet next door. That's why submeters are where parks end up — each tenant billed for their own gallons at cost. When you're ready, here's how to switch your park from RUBS to submeters (Oregon in particular requires a formal process), the state rules on submetered billing, and the water submeter calculator for once the meters are in.
Common questions
What is RUBS?
RUBS (ratio utility billing system) divides a master-meter utility bill across tenants by a formula — evenly, by occupants, or by square footage — instead of measuring each home's actual use. It's how master-metered parks recover water costs without installing submeters.
Is RUBS legal in my state?
It varies. Most states allow it with proper lease language and disclosure, some cities restrict it, and Oregon requires a formal conversion process (ORS 90.574) before you change how you bill utilities. Check your state's rules and put the method in the lease before you send the first bill. Not legal advice.
Should I hold back a park share before splitting?
Usually, yes. The master meter includes common-area use — irrigation, an office, a laundry room, leaks in the park's own lines — and that part is fairly the park's to absorb, not the tenants'. That's the park-share field above.
Is RUBS or submetering better?
Submeters. Each tenant pays for exactly what they used, at cost, and disputes end at the meter read. RUBS is the workable bridge while your park is still master-metered — and the reason high users have no incentive to fix a running toilet. When you are ready, see our guide to switching a park to submeters.
Lot Sidekick bills submetered water from real meter reads at cost — a manager keys the reads from a phone, and every tenant's bill itemizes their own usage. See how it works or call (425) 405-0734.