MWRA online - home
Water System
Sewer System
Harbor and Bay
School Program
About MWRA
Doing Business with MWRA
Contact MWRA

Finances and Community Charges
Massachusetts Water Resources Authority

MWRA is an independent authority established by state statute that provides water and sewer services to 61 cities and towns.

Each year the MWRA Board of Directors must approve an annual operating budget and capital spending plan as well as community assessments adequate to cover all planned expenses. Each MWRA member community, in turn, establishes local water and sewer charges to support both the community’s MWRA assessment and the cost of operating the local water distribution and wastewater collection system.


MWRA is a "wholesaler" to its member communities.  MWRA's charges ("community assessments ") typically represent about 45% of the amount that communities bill their customers. The proportion varies considerably among communities. Each community has its own rate structure and accounting policies.

Water Rates

In setting water rates, MWRA first identifies through its budgeting process the total amount of revenue that must be raised to run the water system.  Charges are calculated using a flat rate per million gallons – $4,387.28 for FY2022 – multiplied by the metered water use by a community in the last full calendar year.

Sewer Rates

Sewer charges are computed on a proportional allocation basis utilizing total flow, contributing population and census population for each community. The total amount of required revenue for the sewer system is allocated either to operating costs or capital costs.  Operating costs are allocated to each community based on the average of the prior three calendar years’ total flow, with adjustments for strength of flow.

Capital costs, including debt service, are allocated to each community based on a combination of (1) average of the prior three years’ peak month wastewater flow and average concentrations of total suspended solids and biochemical oxygen demand; (2) the proportion of the population of the community that is served by the local sewer system; and (3) the proportion of the community’s U.S. census population to the total census population in the sewer system.

Allocation of Total Sewer Charges
Pie Chart - MWRA Sewer Rate Allocation

The MWRA Advisory Board publishes an Annual Retail Rate Survey.

Updated August 5, 2022