Have water tight contracts.

I would make sure the lease is watertight so that if you have any issues with them during the year, you would be within your landlord's rights if you have to evict them. 

Be aware that windows can require permits and have a lot of specifications on how they are installed… like the framing around the windows, flashing to make sure they are water tight, etc.

The top sheet has glue on it, which gives an air and water tight seal to them.

I like sheet vinyl in the bathrooms because it is water tight.

Lastly, practice, consult with BP, "ask around" TO MAKE WATER TIGHT LEASES. 

I am looking at buying a really nice property that has failed it septic inspection due to not being water tight. 

@Troy Whitney My son is a union carpenter in Seattle and area, he recently worked on a multi story apartment building the developer was using components from a EU country-maybe Poland-they got most of the building up-walls and floors-the building started to accumulate moisture inside the wall components which were very water tight and would not release the liquid.

Vegetation should be pruned and/or removed as necessary to maintain a one foot clearance between it and the structure's exterior.23) Exterior Limitations: Unless specifically included in the inspection, the following items and any related equipment, controls, electric systems and/or plumbing systems are excluded from this inspection: detached buildings or structures; fences and gates; retaining walls; underground drainage systems, catch basins or concealed sump pumps; swimming pools and related safety equipment, spas, hot tubs or saunas; whether deck, balcony and/or stair membranes are watertight; trees, landscaping, properties of soil, soil stability, erosion and erosion control; ponds, water features, irrigation or yard sprinkler systems; sport courts, playground, recreation or leisure equipment; areas below the exterior structures with less than 3 feet of vertical clearance; invisible fencing; sea walls, docks and boathouses; retractable awnings.

That is my current understanding, but I will clarify and make sure that's 100% water tight.