See Editors’ Note at the end of this article. After this edition of the Acton Exchange was sent to production, we learned that the outdoor water use restriction has been relaxed back to 2 days per week, effective August 8, 2025.
The summer of 2025 has been unusually dry, as evidenced by the number of brown lawns and withering gardens in the region. During the months of June and July, only about 4.25 inches of rain were recorded by the National Weather Service at Hanscom Field, which is well below the average for those months. This has resulted in a drop in the depth of the Acton’s underground aquifers and a reduction in the flow of local streams. On July 26, the Acton Water District (AWD) issued a Level 3 Water Use restriction which limits outdoor water use to one day a week. The motivation for this change was not a loss of pumping capacity in the Water District’s wells, but rather a state-imposed regulation triggered by the current flow rate in Nashoba Brook.
To protect the health of local rivers and streams, the Massachusetts Department of Environmental Protection has placed withdrawal restrictions on towns that supply potable water from a system of wells. This has been done under the federal Water Management Act (WMA), which was enacted in 1986. The imposed limit is different for each town, and is computed using models developed by the state. The number for Acton is currently 1.94 million gallons per day; to meet peak demands, the District has the pumping capacity to supply water at twice that rate.
In May, 2024, the District received an amended WMA permit, which required the District to revise its seasonal outdoor water use restrictions to align with the requirements of the new permit. The District is now required to monitor the US Geological Service stream gauge on Nashoba Brook in North Acton. When the 7-day low-flow rate falls below 0.57 cubic feet per second for three consecutive days, a one-day-per-week outdoor water use restriction must be imposed. In recent months the flow in Nashoba Brook has dropped precipitously, as illustrated in the chart below.
Although Acton received nearly three inches of rain during the storms on July 31 and August 1, no significant rain is predicted in the long-range weather forecast. The Acton Water District manager, Matt Mostoller, has indicated that the current Level 3 restriction will not be changed until there is a significant increase in the flow in Nashoba Brook for an extended period. Mr. Mostoller also stated that while aquifer levels have dropped in the last few months, there has been no reduction in the Water District’s pumping capacity. Despite the recent rain deficit, the Massachusetts Drought Management Task Force lists Acton’s current drought status as Level normal.
To moderate peak demand for potable water, the Water District has divided the Town into four quadrants, each of which has a different day designated for nonessential outdoor water use. Restricted activities include lawn watering and landscape irrigation via sprinklers and automated irrigation systems, pool filling, vehicle washing, and washing of exterior surfaces. Hand watering of lawns, gardens, and ornamental plantings is not restricted, but should be performed before 7 a.m. and after 7 p.m. to reduce evaporation.
Summer restrictions on outdoor water use have been in place in Acton for many years, and the overall rate of compliance by residents has been extremely high. In a recent conversation with this reporter, AWD Manager Matt Mostoller conveyed that this level of cooperation is greatly appreciated by the Water District, and he extended his thanks to the District’s customers for their outstanding conservation efforts.
Editors’ Note: After this week’s edition of the Acton Exchange had been sent to production, we learned that the Acton Water District has relaxed the outdoor non-essential water use restriction back to 2 days per week, effective August 8, because the stream flow in Nashoba Brook has been well above the threshold of 0.57 cubic feet per second for multiple days. The quadrants for determining your watering days remain as shown in the map above; however more days are allowed, as follows:
- North Acton (green): Tuesday & Saturday
- Central Acton (purple): Wednesday & Saturday
- Southwest Acton (red): Thursday & Sunday
- Southeast Acton (blue): Friday & Sunday
Dr. Parenti is a member of the Town of Acton Water Resource Committee and the Acton Water District Finance Committee.
