Lawn Advice

How would I go about getting my lawn lush and green in the most timely manner.

Just moved into a rental property, previous tenants obviously didn't take the best care and they did have a dog which urinated over the grass, I've read this could have caused damage to grass.

What I've done so far: -Sprayed selective weed killer -Applied organic lawn dressing and compost -Applied ash from hardwood fire very lightly -Watered on a weekly basis

The shed does have a greywater tank connected to my washing machine, is it advisable to use the water after washing over the lawn to water more often