How to split a shared water bill in a small HOA (without a neighbor feud)

A lot of small townhome communities have one water meter at the street and one utility account for the whole property. Every billing period, somebody on the board opens a bill for the entire building and has to decide what each household owes.

The first year, most boards just divide by the number of units. Then someone notices that the household of five next door runs the dishwasher twice a day, while the retired couple on the end is traveling half the year. Now an unfair split is quietly becoming a neighbor problem.

There is no single right way to split a shared bill. There is a right process: pick a method your governing documents allow, write it down, and apply it the same way every time. Here is how.

Start with what your declaration says

Before you pick a method, find out which ones you are allowed to use. This is the step boards skip, and it is the one that matters most.

In Washington, the default under RCW 64.90.480 is that common expenses are assessed by each unit's common expense liability. That is the percentage set in your declaration, often tied to unit size or split equally. If your water bill is treated as a common expense and your declaration is silent, that default formula is what applies.

The same statute lets a declaration choose a different basis for utilities. If the declaration provides for it, the association must assess the cost of specified utilities "in proportion to respective usage, whether metered, billed in bulk based on unit count, or reasonably estimated."

So read your declaration for language about utilities, metering, or usage-based assessments. Three outcomes are common:

• It already authorizes usage-based billing. You can bill by meter reading.
• It sets an allocation formula and says nothing about usage. You are on the default formula until owners amend the declaration.
• It is unclear. Ask an attorney before you change anything. An hour of review costs far less than refunding a year of bills.

Other states handle this differently, so check your own statute alongside your documents.

The four ways to split the bill

1. Equal shares

Divide the total by the number of units. It is simple and needs no equipment, and it is the most common method in very small buildings. It is also the least fair when households differ a lot in size or habits, and it gives nobody a reason to fix a running toilet.

2. By allocated interest

Use each unit's common expense liability from the declaration. This is the Washington default and needs no extra work, but it reflects unit size, not water use. A large unit with one occupant pays more than a small unit with four.

3. By occupancy

Split by the number of people living in each unit. It is closer to actual use, but it relies on self-reporting and has to be updated whenever someone moves in or out. It can also feel intrusive. Most boards that try it drop it.

4. By submeter

Install a meter on each unit's water line and bill each household for what it actually used. This is the fairest method, and it turns leaks into a visible number instead of a mystery. It costs money up front and requires your declaration to authorize usage-based billing.

Separate fixed charges from usage charges

Most utility bills combine two kinds of charges. Some are fixed: base service charges and flat fees that would be the same if nobody turned on a tap. Others depend on volume: water used and, often, sewer charges calculated from water use.

The cleanest approach for a submetered community is a hybrid: split the fixed charges equally, and split the usage charges by meter reading. Nobody should pay more of the base service charge just because they use more water, and nobody should get it free because they use less.

A worked example

Take a hypothetical six-townhome Seattle HOA with submeters on each unit. This billing period's combined water and sewer bill is $1,140. Of that, $180 is fixed charges and $960 is based on usage.

Fixed charges split equally come to $30 per unit. Usage charges split by meter reading:

Under an equal split, every unit would owe $190. Unit B would be overpaying by $64 every billing period, and Unit C would be underpaying by $51. Over a year, that adds up to the kind of number people bring up at the annual meeting.

Two details to get right:

• Use shares of metered usage, not raw gallons times a rate. The submeters will never add up exactly to the master meter. Common-area use, irrigation, and normal meter variance all show up in the gap. Allocating the actual bill by each unit's share means the totals always reconcile to what the utility charged.
• Decide in advance how to handle common-area water. If the HOA waters landscaping off the same meter, either treat that as a common expense in the operating budget or include it in the shared fixed portion. Write down which.

Put the process in writing

Whatever method you choose, adopt it by board resolution and give it to every owner. A one-page policy should cover:

1. The method and its authority. Which split you use and the declaration section that allows it.
2. The schedule. When the utility bill arrives, when owners get their share, and when it is due.
3. What owners see. Attach the utility bill, or a summary of it, to every split, so anyone can check the math.
4. Leaks and anomalies. If a unit's usage spikes, the board notifies that owner promptly. A submeter that catches a leaking toilet in week one saves that owner real money.
5. Disputes. How an owner asks for a review of a reading, and who decides.

One more Washington-specific caution: keep the bill addressed to the owner. If an owner rents out their unit and the HOA starts billing the tenant directly, landlord-tenant utility billing rules can come into play. The owner can settle up with their tenant. The association bills its members.

Make it boring

The goal is a split nobody thinks about. The bill arrives, shares go out, everyone can see the math, and payments land on schedule. A shared utility bill becomes a neighbor problem only when the method is unclear or applied inconsistently.

Fourplex reads each unit's water submeter, bills every household for its own usage, and can split a shared trash bill on the same schedule. Owners pay through the resident portal, and the money goes directly into the association's bank account. But a spreadsheet and a written policy will get you most of the way. What matters is that the method is authorized, documented, and the same for everyone.

This is general information, not legal advice. Confirm what your declaration and state law allow before you change how your community splits a shared bill.