Check your metered water supply/waste bills. Starting with your billing data, this allows you to calculate your correct bill.
It has its own internal help screens, backed up by my website.
It is all completely ad free.
It allows for separate Supply and Waste companies. Each can have their own tariff change date [Split Date].
Charges are calculated to 2 decimal places: for standing charges [dates] and volumetric charges [readings].
VAT [Sales Tax] can be added if applicable.