The town is asking water customers in Danvers and Middleton to make a special effort to conserve water during October because of construction work at the Vernon C. Russell Water Treatment Plant. The plant, on Lake Street in Middleton, treats water from Middleton Pond Reservoir, the primary water supply for Danvers and Middleton, and from nearby Emerson Brook. Danvers, which also has two wells, supplies water to both towns. The $24 million construction project is designed to enhance the effectiveness of the plant’s treatment, improving water quality and allowing the plant to meet drinking water requirements for the next 20 years. As part of the 24-month project, which is about half complete, the plant will be shut down for the entire month of October. The town plans to use its wells and to purchase water from the Salem-Beverly water system during that time. But officials said a reduction in water use is also needed. Customers are urged to refrain from any outdoor water use and to try and reduce household water use. Officials also say that people might detect a slight discoloration of their water and a mild chlorine odor due to a temporary change in disinfection methods during the shutdown. The water remains safe for drinking and bathing. Meanwhile, the town is holding its annual household hazardous waste collection day Saturday from 8 a.m. to noon at the transfer station, on East Coast Road. The drop-off is for Danvers residents only. For more information, go to the Department of Public Works page on the town’s website, www. danvers.govoffice.com.