Which of the following is a source of excessive clear water in a collection system?

• A. A problem at the wastewater treatment plant
• B. Water distribution main construction project
• C. Infiltration from a high water table
• D. Evaporation

Answer: (C)

Infiltration of groundwater from a high water table is the source of excessive clear water in a collection system. Groundwater is naturally clean, so when it leaks into sanitary sewers through cracks, leaky joints, faulty connections, or around manholes, it adds large volumes without bringing in wastewater. This extra, clear water increases the flow within the system, which can lead to overloading, surcharges, and more pumping needs. The other options don’t describe this persistent, clean-water inflow: a treatment plant problem affects downstream treatment, not the amount of water entering the sewer; a water distribution main project can cause temporary inflow but isn’t the typical ongoing source; evaporation removes water rather than adds it.