Inflow and infiltration is a moving target, but the Plano (Texas) Public Works Department has it in its sights. The utility sees a 28 mgd flow, and while it isn’t known yet precisely how much is I&I, it’s known that outside water is invading the system. And the city is on the case.

“We still are in the assessment stage,” says Abby Owens, strategic planning and compliance manager at the Plano Public Works Department. “We are trying to get a handle on the situation,...