Are water bills all the same within a water bill collecting area and other fees like specials take care of maintenance/new construction?
It depends on local regulations. Some communities are pretty even across the board. Others may charge industrial/commercial different rates due to increased usage (larger pipes, more outflow, etc..). Others may have different districts that get credits based on where their water goes, age of pipes, etc.. Others provide service to rural customers and they generally get charged a higher rate than people within the service area. Even other areas will be levied under special taxes for the particular area, where the citizens of a neighborhood pay extra fees/taxes to pay for new pipes over a 10-15 year period. <- these generally happen in new development areas.
Water itself, on average, costs like a tenth of a cent a gallon, so it is dirt cheap regardless of where you live.
Wastewater, for many communities, is calculated when your water usage would generally be at its lowest (winter months). The water utility will average out the amount of water usage from like November through February, and then calculate your monthly sewer charges for the next year off of that. So months where a lot of the water usage doesn't end up in the Sanitation sewer (yard watering, pool filling, etc..), isn't taken into account. If you want to shave a few dollars of your bill, limit water usage as much as you can during the winter.
Storm Sewers are a different animal and every community does them differently. In general, most communities use some formula based on the amount of impervious area on your property that would lead to stormwater runoff. The formula generally includes what the landuse of the property is as well. Most communities don't try to calculate the amount of impervious area on a single family property, so a lot of times, all those properties will just get charged the same fee, regardless of size. Some put that as a monthly charge in your water bill, others just tack on that amount in your end of year property taxes. etc... This is why you'll often find retention ponds on or near areas with lots of pavement as a company like walmart can get a huge discount on their stormwater fee if they route the water to their own storage pond.
You didn't ask for all that, so sorry for the extra info.