We run a small (365 connections) water system which has about 75% of the connections at summer cottages which are shut-down every winter. We have noticed a trend of total coliform hits in October/November when these cottages are being shut down. Virtually all of the cottages have a drain-back valve in the yard between the cottage and our curb stop. We are aware that, through word-of-mouth, an increasing number of cottage owners are using a compressor to blow air through the plumbing after closing the drain-back valve in an effort to avoid coming back to plumbing leaks in the spring. We believe this may be a possible source of the contamination.
Following our most recent coliform hit in November, the State Health Department is requiring that t "a standard operating procedure be published and distributed to homeowners describing the proper methodology for the seasonal shutdowns of their homes. This procedure should specifically exclude the use of air compressors for dewatering."
Anyone have a good SOP I can use as a starting point?