Remedies for brown patches:
If practicable, regularly water your lawn
Eradicate lawn diseases
Deter lawn pests
Have annual core aeration and machine scarification
If practical, have a designated area for your dog to urinate
Cut the lawn using the highest setting on your lawnmower
Brown patches on a lawn can occur for a number of different reasons:
What the lawn was laid on and the turf quality
Leaving something on the lawn for a prolonged period of time