Just a heads-up. When I got my 2015 sewer tax bill, I was surprised with the increase over last year's bill. I know there was a 2.5% rate increase but that didn't justify the increase I received.
So, I compared the water usage (in gallons) on my sewer tax bill to the actual water usage on my Edison Water Company water bills for calendar year 2014 (the year used for sewer tax purposes).
The water usage on my sewer tax bill was some 9,000 gallons more than the actual water usage on my water bills. Since these usage numbers are reported to the town by the water company, I've been trying to get an explanation for the discrepancy and all they will say at this time is that they checking into it and will provide a call-back when they resolve it.
So, it might be prudent to check your actual water usage from your 2014 water bills to what's being charged on your 2015 Sewer tax Bills.
Don't know how this effects non-residential customers, if at all, but you might want to check it out too.