If you have sewers, but the residents can't connect, they will need larger lots to support the leaching field
Traditional leaching field
systems are prone to failure due to soils with low, or very high, permeability.
The upper plume moved along near the surface of the water table and contained the highest nitrate concentration of the three plumes; at nearly 3000 [micro]M, it was similar to literature values  for septic effluent that has just left the leaching field
The flow is measured and then goes to a leaching field
through a dosing chamber.
Our water storage reservoirs and leaching fields
are located in the north San Fernando Valley.
By filtering out the majority of the wet waste solids, fats, oils and greases "at source," the potential for water pollution from raw sewage spills from municipal sewage treatment plants and septic tank leaching fields
overflows are reduced.