Often wonder a backyard utility sink or Laundry tub. Maybe to clean paintbrush's etc . Where would you discharge the water from the P-trap. In the back yard there is no septic tank nor sewer. The sink would only be occasionally used.

If this were my call I build me a dry well, (see image) Good luck, Tom

Wow that is wonderful

If it's an outside sink you don't even need a P trap since there is no sewer hookup. I rural areas, just a hole with rocks will suffice.

Very Good

ust a hole with rocks will suffice. Hey Brain, We call that a "dry well". Tom

Very Good