The reason why urine turns grass brown or yellow has to do with chemistry. Understanding why this happens is your first step toward preventing it and retaining your nice lawn.
Nitrogen is an essential component of healthy soil, but high concentrations of it can cause patches of grass to die and turn yellow or brown. Urine is naturally rich in nitrogen, and high concentrations of nitrogen can cause grass burns. Lawn fertilizer also contains nitrogen. Oftentimes the dead grass is surrounded by an exceptionally lush, green ring of growth, which occurs due to the fertilizing effects of lower concentrations of nitrogen.
Salts and other compounds found in dog urine may also contribute to grass damage. Highly acidic or alkaline urine may alter the pH of the soil, adversely affecting the grass in the areas of the yard where your dog urinates.
Use water to immediately rinse off the area after your dog urinates. Encourage your dog to urinate in a different area each time so the urine and the watering are spread out.
Please note* the condo board will not pay for the repairing of grass damaged by a pet.
Source: https://www.thesprucepets.com/dog-urine-brown-spots-on-grass-1118287
