I totally agree that the rules the state/city/local providers have published are confusing to say the least. Some rules are in conflict, and it’s hard to say who’s rules take precedence. As we are the ones that are required to comply with these rules, it certainly makes it difficult to do so.
My local provider (San Jose Water Company) recently published a table and surcharge plan (that hasn’t yet been approved by the PUC as of yet) that gives some specifics about how they plan to meter usage and charge for overages. I went back through the last years worth of bills, extracted our water usage and compared with the table (a rough estimate as we are billed every two months and the table is monthly). We were significantly over in all but the past billing period (which could be explained by repairing a leaky toilet flapper and irrigation scheduling changes around the end of the year). I would love to be able to automate this and send warnings if usage was trending towards running over, but our water meters are mechanical 🙁