Water District Commissioners vote to renew outdoor water use restrictions

June 7, 2024

Outdoor water use restrictions for the summer of 2024 were unanimously approved by the Acton Water District commissioners at the regular meeting of the commissioners on 29 April. District Manager Matthew Mostoller noted that Acton’s aquifers are currently in very good shape, but indicated his intention to impose a two-day-a-week restriction beginning on May 1. Mr. Mostoller also stated that this could be reduced to one day per week in the event that Acton experiences an unusually dry summer.

Although the Acton Water District has found it necessary to impose seasonal outdoor water use restrictions for many years, customers might question the need this year given the amount of rain that the region has received this spring. The Commissioners’ decision to approve limits this summer is based on several factors:

  1. State-mandated regulations – Acton’s Water Management Act Permit establishes limits on the yearly average daily withdrawal of water from the Town’s aquifer, which is currently set at 1.94 million gallons per day (MGD). That document also requires that nonessential outdoor water use for each customer be restricted to two days per week. That number can be reduced to one day per week if the Nashoba Brook stream flow falls below a preset threshold.
  2. Capacity losses resulting from actions taken to reduce PFAS levels – Water suppliers in Massachusetts are currently required to maintain a PFAS level that is less than 20 parts per trillion (ppt). Raw water levels in Acton tend to range from 5 ppt to 40 ppt, which is typical for towns in the MetroWest region. Plans are underway to add permanent treatment for PFAS to the Water District’s three treatment facilities, but until that work is completed the District Manager has been using a variety of approaches to reduce PFAS levels. These measures include using water sources selectively and pumping wells at below-nominal rates. These actions have significantly reduced the Water District’s cumulative supply capacity.
  3. The need to limit peak demand – Peak demand is a critical parameter in the design and operation of any public utility. As shown in the chart below, peak demand in the summer months due to lawn watering often exceeds the average daily demand by 50%. Such spikes in water usage, in conjunction with the required PFAS-related capacity reduction, greatly complicates the task of maintaining the requisite water pressure throughout the distribution system. Proper management of the Water District’s resources is essential to ensure uninterrupted water service to all Acton residents, as well as to leave an adequate reserve for the Fire Department in the event of an emergency.
Graph with X-axis years from 2004 - 2020. Y-axis is Volume of Water (mgd [millions of gallons per day). The Water Management Act permit shows as a straight red line at 1.94 MGD. A second line shows maximum daily demand. It ranges over the years from a high of about 2.7 MGD to very close to the 1.94 permit line, with a steady downward trend beginning in 2016. The third line shows average daily demand, which hovers between about 1.5 and 1.9 MGD.
Historical water usage data, millions of gallons per day. Photo: Ron Parenti. Data from AWD sources.

To deal with these concerns, the Water District has developed the outdoor water use schedule delineated below to moderate peak summer demand. As indicated, the Town is divided into four quadrants, each of which has an assigned 2 day per week schedule. Since a significant amount of water is lost due to evaporation during the hottest times of the day, lawns can be watered only before 7 a.m. and after 7 p.m. Fines of up to $200 can be levied for a violation of these rules; however, due to the high level of compliance with the watering regulations, the Water District has seldom found it necessary to employ this option.

A map of Acton with several colored areas showing the days that non-essential watering is allowed in various parts of town. In general, lawn and other non-essential watering is allowed as follows: - North Acton - Tuesday & Saturday - Acton Center/East Acton - Wednesday & Saturday - West Acton - Thursday & Sunday - South Acton - Friday & Sunday
Outdoor water use summer schedule. Photo: Ron Parenti. Data from AWD sources.

Long-time residents of Acton have become accustomed to the summer watering restrictions, and District Managers both past and present have frequently expressed their gratitude for the high level of cooperation that they have received from the public. Looking further into the future, it is worth noting that it is unlikely that seasonal limits would be eliminated if a decision is made to connect to the MWRA, since the amount of water that Acton would be able to withdraw from that source will be strictly limited due to the number of MetroWest towns that would be served by that connection.

Dr. Parenti is a member of the Town of Acton Water Resource Committee and the Acton Water District Finance Committee.


Help support the cost of bringing accurate, relevant news to the Acton community.


Sign up to receive a weekly email newsletter providing links to our new articles.


Look here to access all articles in your areas of interest.