1992 - septic system failure & replacement

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TO: File - 2095 Webber Hills Road FROM: Stephen Weckman, On-site Systems Manager DATE: November 18, 1992 RE: Septic System Failure and Replacement The purpose of this letter is to provide additional information regarding the septic system failure and subsequent replacement. For additional information see memo to file dated September 21, 1992. The old septic system was installed by Widmer Brothers in 1966 under permit #1228. The septic system includes two concrete block tanks with capacities of 1 , 000 and 500 gallons respectively and approximately 500 sq. ft. of drainfield trenches. The owner of the property requested a septic system inspection which was completed on July 9, 1992 at which time the system was observed visibly discharging untreated effluent to the surface requiring repair within ninety days of the inspection date. Prior to this inspection there is no indication from previous inspections that the septic system was likely to fail in the near future. The original septic system was presumably inspected when installed and met the code requirements as they were administered at the time. The City's inspection report dated July 11, 1978 indicated the system was substandard under the new 1978 code based on the information available. A fully conforming system would have needed two sealed 1,000 gallon tanks and an amount of drainfield based on the number of bedrooms and the soil capabilities as determined from percolation rate, water table depth, and other site factors. The drainfield at 2095 Webber Hills Road appeared to be too small for the house given the probable soil conditions and was potentially too near the water table. The septic tanks were also noted to be undersized and of concrete block construction and may not be watertight. The system was functional at the time and remained classified as a substandard system until it was observed surfacing on July 9, 1992 at which time it was considered non-conforming and requiring repair. The exact cause for the system failure is unknown. Failure can occur due to the proximity of the system to the seasonally high water table and annual fluctuations of the water table, system maintenance, soil or site limitations, or increases in water usage. Of the 31 homes built between 1965 and 1975 on Webber Hills and Shevlin Roads, 12 systems have been replaced or repaired as of 1992. The high percentage of repairs/replacements in this neighborhood suggests that many of the original systems had a useful life of 15-20 years. In theory a system designed and constructed according to current codes could function indefinitely.