Which source is a source of excessively clear water in a collection system?

Which source is a source of excessively clear water in a collection system?

• A. A problem at the wastewater treatment plant
• B. A sanitary sewer leak
• C. Exfiltration from a high water table
• D. Infiltration from a high water table

Answer: (D)

Excessively clear water in a sewer system comes from groundwater entering the pipes, not from wastewater. This inflow is called infiltration, and it happens when groundwater from a high water table seeps into the sewer through cracks, joints, or defective manhole rims. A higher water table means more groundwater is available to infiltrate, so infiltration from a high water table becomes a major source of that unusually clear water. Why the other scenarios don’t fit: a problem at the treatment plant affects treatment performance rather than what enters the sewer, a sanitary sewer leak would release wastewater into the surrounding soil rather than introduce clear water into the system, and exfiltration from a high water table would cause sewer water to escape into the soil, not enter the sewer. So the source of the clear water is infiltration from a high water table.

Excessively clear water in a sewer system comes from groundwater entering the pipes, not from wastewater. This inflow is called infiltration, and it happens when groundwater from a high water table seeps into the sewer through cracks, joints, or defective manhole rims. A higher water table means more groundwater is available to infiltrate, so infiltration from a high water table becomes a major source of that unusually clear water.

Why the other scenarios don’t fit: a problem at the treatment plant affects treatment performance rather than what enters the sewer, a sanitary sewer leak would release wastewater into the surrounding soil rather than introduce clear water into the system, and exfiltration from a high water table would cause sewer water to escape into the soil, not enter the sewer. So the source of the clear water is infiltration from a high water table.