Water submeter calculator
Enter the two meter reads and your utility's rate. No markup. Bill what you paid.
Billing the whole park, not one lot? The water billing run takes a pasted sheet (or your reader's export) of every meter's reads and hands back an itemized bill per lot — print, PDF, or CSV.
How to compute a submeter water bill
The calculator above does exactly this. If you want to check it by hand (or you're at the meter with a notepad), it's five steps:
- Read the meter and write down the number (the face says whether it counts gallons or cubic feet — one cubic foot is 7.48 gallons).
- Subtract last month's read from this month's. That difference is the tenant's usage.
- Multiply the usage by your utility's per-gallon rate — the rate from your own bill, not a number you pick.
- Add your base fee, if your state allows passing one through.
- Put it all on the bill: prior read, current read, rate, service period, and the total.
Worked example: last month's read was 41,200 and this month's is 45,700, so the tenant used 4,500 gallons. At $0.0178 per gallon that's $80.10, plus a $2.00 base fee — $82.10 on the bill.
Reading the result
This calculator does what a submetered bill should: it takes the difference between the two reads, multiplies by your utility's rate, and adds your base fee. No markup. A tenant's bill should itemize the prior read, the current read, the rate, and the service period, so it's obvious the charge is at cost; that itemized read is also your answer if a bill is ever disputed.
For the full picture (the master-meter-vs-submeter tradeoff and the state rules), read submetered water billing rules by state and how to bill tenants for water the legal way. Still splitting a master-meter bill? Use the RUBS calculator for a clean split, and here's how to switch your park to submeters. Wondering how other owners handle the whole billing job? We read a decade of forum threads on what small-park owners use and pay.
Common questions
How do I compute a submeter water bill?
Subtract last month's meter read from this month's read to get gallons used, multiply by your utility's per-gallon rate, and add your base fee if your state allows passing one through. Example: reads of 41,200 and 45,700 are 4,500 gallons; at $0.0178 per gallon that's $80.10, plus a $2.00 base fee is $82.10. Itemize both reads, the rate, and the service period on the bill.
What if my meter reads in cubic feet, or my rate is per CCF?
Pick the units in the calculator and the conversion is done for you. Doing it by hand: multiply cubic-foot reads by 7.48 to get gallons; divide a per-1,000-gallon price by 1,000; divide a per-CCF (hundred cubic feet) price by 748.
Can I add a markup to a submetered water bill?
In most states, no — submetered water must be billed at cost, at your utility's rate. Some states let you pass through a reasonable base or service fee; the rules differ, so check your state before adding one. Billing at cost is also what keeps disputes short: the meter reads are the answer.
Where do I find my rate?
On your own utility bill. Use the volumetric (per-gallon) portion for the usage math. If sewer is billed on water usage and you pass it through, use the combined per-gallon amount and show it as its own line so the bill stays at cost and easy to check.
Lot Sidekick does this on every bill automatically. Your manager keys the reads from a phone and each tenant's water line is itemized at cost. See how it works or call (425) 405-0734.