whatwatercosts.org
Machines can read America's water rates with ease. Finding them is another matter, and the smaller the utility, the harder it gets.
Water rate schedules are not light reading. They come thick with tiers, meter sizes, billing periods and surcharges bearing names such as "DSIC" and "PWAC". When we set an AI agent to work on them, we assumed reading would be the difficult part. It was not. The difficult part is finding the right document in the first place.
whatwatercosts.org publishes a standardized monthly water bill for thousands of American utilities. An AI agent reads each utility's official rate schedule; ordinary code does the arithmetic. Having run that process on every system serving 10,000 people or more, one conclusion stands out. Most of our effort, most of our cost and most of our mistakes come not from reading but from searching.
Reading is the cheap bit
Where does the effort go? The agent's logs give a rough answer:
| Step | Share of effort |
|---|---|
| Searching the web for the right document | about 45% |
| Writing and checking the structured result | about 28% |
| Reading its own instructions | about 17% |
| Reading the rate schedule itself | about 9% |
Nearly half goes on the hunt: trying queries, opening pages, discarding budget summaries and local news, and confirming that a document covers this utility and not its neighbor. The part we expected to be hard accounts for less than a tenth. (The split is approximate; the agent sometimes reads pages through its search tool, which blurs the line.)
Wrong place, wrong rates
Search is not merely costly. It is also where things go wrong. When we audit our bills against official schedules, the worst errors seldom come from misreading a document. They come from reading the wrong one:
- Last year's rates. A city's rates page still announces prices "effective October 1, 2025", while the council has quietly adopted new ones in a separate resolution.
- The wrong utility. We priced six small Californian systems from a neighboring city's rate sheet; the documents looked alike and lived on related websites.
- Proposed, not adopted. A hearing notice prints proposed rates beside current ones, and the wrong column gets used.
- Summaries, not schedules. A budget document or newspaper quotes a rate that no customer actually pays.
The smaller the utility, the emptier the web
Sometimes there is nothing to find at all. When we researched every one of California's water systems, the odds that a current, official schedule was online fell sharply with size:
| Utility size (EPA category, people served) | Systems researched | No current rate schedule found online |
|---|---|---|
| Very large (over 100,000) | 90 | 16% |
| Large (10,001-100,000) | 356 | 16% |
| Medium (3,301-10,000) | 223 | 18% |
| Small (501-3,300) | 512 | 41% |
| Very small (500 or fewer) | 1,612 | 80% |
Among medium-sized systems and larger, roughly one in six has no schedule we could find. Among the very smallest, four in five. Mobile-home parks, schools and small mutual water companies often share their rates only on a paper bill, by post or at a board meeting. Nor is a search for a small town any cheaper: researching a system of 10,000 people takes about as much effort as one of 500,000, because the hunt, not the size of the utility, drives the cost.
That matters for anyone who cares about affordability. Small systems have fewer customers over whom to spread fixed costs; the Congressional Research Service notes that their infrastructure needs "result in higher per-household costs" than in larger systems, by as much as two to three times (CRS, 2023). Our own data agree: in California, a typical household in a very small system pays about $95 a month, half as much again as the $65 paid in the largest systems. Small systems are where a published rate schedule would do the most good, and where one is least likely to exist.
What would fix it
The solution is a maintained registry of current rates, ideally validated by utilities themselves or pointing to sources they confirm. We are working on one.
In the meantime, utilities and residents can help. On any utility's page on whatwatercosts.org, use "Suggest a correction" (or submit a rate schedule) and include:
- a link to the current, official rate schedule (or the document itself);
- the date the rates took effect;
- anything that applies to households but isn't in the schedule, such as a separate fee resolution.
Water rates are public information. Finding them should not require a research project, least of all for the small towns where the bills bite hardest.