Town Talk: Residential sump pump inspections completed in 2017
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The New Ulm Public Utilities (NUPU) Wastewater department finished its third and final season of residential sump pump inspections in August 2017. Of the 4,675 residential properties in New Ulm, 1,900 were inspected in 2015, 2,400 were inspected in 2016 and 996 this past summer. 23 percent or 1,068 houses were found to have sump pumps with 8 percent or 84 of the homes inspected were found to have sump pumps discharging illegally to the city sanitary sewer.
I thought the NUPU did a great job with public relations, education and informing the citizens of our sump pump inspection program. The residential inspections took three years to complete so we assume homeowners were proactive and corrected their sump pumps before the inspections staff made it to your neighborhood. Although we revised our inspection forms numerous times we didn’t think to ask the homeowners if they had corrected their sump pump discharge before we arrived. With that said, the 8 percent failure rate is on the low end.
Although hard to quantify what impact we had on inflow at the wastewater plant, using conservative numbers: If the 84 illegal sump pumps ran 60 minutes a day and pumped 10 gallons per minute we removed over 50,000 gallons inflow a day or about 10 million gallons over the six wet weather months of concern. This has an approximate cost savings to the NUPU rate payers of $50,000 annually.
The NUPU targeted sump pumps as we continue our efforts to minimize inflow and infiltration (I&I) problems in New Ulm. It was suspected that many homes have sump pumps that discharge into the sanitary sewer system, which is an illegal connection. Illegal connections to the sanitary sewer can lead to sewage backups. It takes only eight sump pumps operating at full capacity to overload an 8-inch sewer main and cause backups which increase health risks.
When sump pumps are connected to the sanitary sewer, clear water is unnecessarily pumped to the Wastewater Treatment Plant increasing pumping costs. Excess flows to the Wastewater Plant can cause the system to reach maximum treatment capacity, resulting in increased chemical treatment costs, or pollutants to pass through the plant without adequate treatment.
The NUPU staff will continue to work on inflow issues and plan to inspect downtown area in the near future and continue to work the city engineering to prioritize sanitary sewer repairs and infrastructure replacement to further eliminate Infiltration.