 The Federal District had a level of non-revenue water of 40%, close to the Mexican average, meaning that only 60% of the water pumped into the system is actually being billed for.A large share of non-revenue water is due not to leakage, but to illegal connections.Furthermore, SACM, the water department of the District, has by far the lowest collection efficiency among the 25 major municipalities, with only 40% of all bills being paid.