In many Costa Rican condominiums the water provider (AyA, a local ASADA or the municipality) installs a master meter and sends a single bill. Management then has to split that amount among the units. There are two ways to do it: by ownership share or by consumption. This guide explains how to do the second one well, since it’s the fairest.
Why bill by consumption
Splitting the bill by ownership share (coeficiente de copropiedad) is simple but unfair: a unit with one resident pays the same as the one next door, where six people live and a toilet has been leaking for months. It also removes any incentive to save, because every wasted liter is paid by everyone.
With individual meters (submeters) per unit, everyone pays for what they use and management can spot leaks before they become a problem.
1. Monthly readings, always on the same day
Billing is only as good as the reading. A few recommendations:
- Same day every month, so periods are comparable.
- A fixed route per tower or street, so no meter gets skipped.
- A photo of each meter when possible: it settles 90% of complaints.
- Capture on site, on a phone or tablet, instead of writing on paper and typing it up later at the office. Every transcription is a chance for error.
2. Calculate consumption and handle the odd cases
Monthly consumption is the current reading minus the previous one, in cubic meters. Two cases deserve attention:
A reading lower than the previous one. The meter may have rolled over (reached its maximum and returned to zero) or, far more often, someone mistyped. If it rolled over, consumption is what was left to complete the cycle plus the new reading. But if that gives an absurd figure, say hundreds of cubic meters for one house, the right move is to reject the reading and take it again, not to bill it.
Unusual consumption. Compare each figure with that unit’s average over recent months. If it’s more than double, flag it as a possible leak and tell the resident before billing. With very little history (a new unit, for example) there’s no point judging.
3. Set the rate in the assembly
How water is billed must be approved by the assembly or set in the bylaws. The most common options:
| Model | How it works | When it fits |
|---|---|---|
| Flat rate per m³ | Master bill ÷ total metered m³ | Simple and transparent |
| Tiered rate | Price per m³ rises with consumption | Encourages saving, mirrors the provider’s rate |
| Fixed + variable | A base amount plus consumption | Covers fixed costs (pumping, tanks) |
Whatever the model, document the calculation and publish it. If common-area water (irrigation, pool, cleaning) is metered separately, that consumption belongs in the general budget, not on the units.
4. The gap between the master meter and the sum of unit meters
They almost never match exactly. The gap can come from leaks in the internal network, common areas without a meter or unit meters that under-read. A small, stable gap is normal; one that grows month after month is a leak alarm in the condominium’s network and worth a plumber’s visit.
Decide in the assembly how that gap is shared: by ownership share, in proportion to consumption, or absorbed by the general budget.
5. Put water on the account statement
The water charge should appear on the same account statement as the maintenance fee, with the previous reading, the current one, consumption and rate. That way residents see a single balance, pay once, and water goes through the same delinquency process as every other fee. For how the general fee is built, see how to calculate the maintenance fee.
Common mistakes
- Reading on different dates each month and comparing 25-day and 35-day periods.
- Transcribing from paper to a spreadsheet.
- Billing an absurd reading “because that’s what it said” instead of checking it.
- Not warning about leaks until a huge bill arrives.
- Changing the rate without assembly approval.
How CondoCMS handles it
CondoCMS’s water module organizes meters by tower, lets you capture readings from a phone, calculates consumption, handles meter rollover while rejecting impossible consumption, flags anything above twice the recent average as a possible leak and posts the charge straight to each unit’s account statement. To see it with sample data, request a demo.
Next step: see metered water.
Frequently asked questions
Is it better to bill water by ownership share or by consumption?
By consumption, as long as each unit has its own meter. Billing by ownership share makes a household of two subsidize a household of six, and removes the incentive to save water and fix leaks. Without individual meters, ownership share is the only reasonable option until they are installed.
What happens when a meter rolls over?
When a meter reaches its maximum it goes back to zero, so the new reading is lower than the previous one. The real consumption is what was left to complete the cycle plus the new reading. The system should detect this, but reject impossible consumption, because a lower reading can also just be a typo.
What should we do if a unit shows very high consumption?
Warn before billing. Consumption over twice the unit’s average usually means a leak. Notifying the resident so they can check their plumbing builds trust and avoids arguments when the bill arrives.