It sounds like you have a fungal disease attacking your lawn. A lot of the fungal diseases appear as round areas that look like they have died from lack of water.
If it were lack of water it should be pretty much even through the area. Droughts do not just attack small areas, and even if it did, a lawn that has turn brown by a drought, will return to green after it has been watered a few times.
If your landlord is a idiot and wants to try to blame it on you, what I would do is call you local Lawn Doctor Inc. They offer a free evaluation of your lawn, in hopes of having you as a customer, for fertilization and
weed control services. When calling them for a appointment make sure to tell them that you think you have a disease, and you would like someone that is familiar with them to check it out. That way you can have something in black and white to hand your landlord, along with a estimate for treating it!
Be careful with watering in the meantime, a lot of diseases are enhanced by too much water or watering in the evening, or a excess of nitrogen (fertilizer)
There is also a fantastic book out there as well, for self diagnoses of things going wrong with a lawn. Ortho puts them out they are called the "All about Lawns" It is part of a series of books that they put out on just about every aspect of
plants, and home repairs. They have excellent pictures, and tells you not only how to fix the problems, but what may have caused it in the 1st place. They are all written in simple everyday English, and very easy to use.
If it is a lawn disease, while I am not a lawyer, but I would take a sample of the lawn. ( part dead area and part live) cut it out with a shovel, and bring it to you local COOP Extension office, where they will be able to give you a report that should stand up in court, if it comes to that.
I hope this helps you out, and if you need anymore help please let me know.
Mike
