Wetdawgs is correct, that would be a hidden defect. Your realtor should have asked you to get a home inspection. The sprinkler system should have been tested, however many times it takes a while for the water to be seen (If the break is under ground). This is a common issue, but really is tough to detect in the amount of time an inspection takes.
You need to find a home that is zoned for residential and business. Call municipalites around were you live and find out were the mixed use zoning aareas are.
On your 90th day of being late, a new department will call you (loss mitigation). They have the power to modify your loans. Before speaking with them you need to identify and prove your hardship
Like mentioned above, make sure the created room is useable, also place the closet in a place that doesn't make it look like it was an after thought
County clerk, also don't overlook sheriff sales