Aerating a compacted lawn lets water and air reach the roots, which can cut irrigation needs by about 30 percent in dry months.
Aerate in spring or fall when the grass is actively growing, using a core aerator that pulls small plugs of soil.
Water deeply but less often after aerating, since deep roots survive drought far better than shallow ones.
Leave the grass a little taller, because taller blades shade the soil and slow evaporation.
A healthier lawn needs less water, and less water means a lower bill.