here's a link for national averages

http://www.cbsalary.com/national-salary-chart.aspx?specialty=Wastewater+Treatment+Plant+Operator&tid=2628&cty=&kw=Water+Treatment+Operator&jn=jn013&edu=&sid=&cbRecursionCnt=1&cbsid=50e05fdb35dc4783b8f2c7b2dfc5601c-324912554-wp-6&ns_siteid=ns_us_g_Yuba_city_wastewater__

You probably want to balance this with local average salaries for your part of the country. I'd imagine east coast salaries are typically on the higher end of the curve.

My advise is to pay your good operators more than what they'd get on the market so they stick around.

I agree with what Ryan has posted about pay rates; you want to check against what other companies offering similar capabilities/services are charging.  Also remember that the East coast is highly influenced by the Davis-Bacon act.   THis means even if you may not be a union shop, you'll have to pay prevailing wage rates which are set by/equal too the going rate of a union shop doing the same work.  Also a lot of the smaller WWTPs in the region have contracts in place with companies such as Veolia Water, Woodard & Curran, CH2M Hill to name a few.  

When in doubt check with the state in which you are about to bid the job to ensure your pay rates are within the guidelines for that area.

Dallas