Abstract: This invention comprises a new and improved apparatus for distributing automatically lawn treatment products, including chemical nutrients, herbicides, fungicides, and insecticides, through a lawn irrigation system using either potable or reclaimed water, and for maintaining the system in good working order. An adjustable multi-outlet watering manifold allows a user to regulate the amount of product to be applied to the particular zone serviced by each sprinkler station. Sediment and contaminants that may be found in the main water source are filtered out before reaching the lawn irrigation system, and the design of the apparatus makes regular flushing of the main water line easy. A liquid pressure gauge allows a user to discern immediately whether an observed drop in water pressure is due to a break or other problem with the main water supply. The configuration of the apparatus provides redundant means of preventing contamination the main water source via backflow.