Sliding doors on rails.

Every time it rains hard the water does not drain properly into the two drains off my porch and my porch disappears under water, then the water starts coming in under the sliding door.

Or do I let it slide and pretend like I never saw it?

It's a lot easier to make a case for discrimination if you let one person slide for something but not someone else.

As they develop more and more of a solid track-record, you can let Rental payments that are 3-6 days late slide a bit more, and offer other benefits such as reduced increases when their Leases are up for renewal, fast service when the maintenance calls come in, keep the hallways & common areas really nice, new  & clean, etc...In any event, professionalism is the key no matter what, imho.

Trust me when I say this you need to be firm in your biz and stick by whatever rules you have made, I am the "good cop" in our biz and I usually have pity on some that tend to need housing but cannot afford the property, guess what when you let some rules slide you have made up with this forum from folks that have been there and done that, you will put yourself in a bad predicament more often than not.  

As for the hot water tank / HVAC pans, it depends, not required that I know of, but if you want one you can go buy it and have anyone install it, just lift the unit up and slide it under.

And now I'm concerned that my lawyer let this slide at the closing table.

There was already some pet damage so I wasn't willing to let the violation slide. 

We then assessed their heating costs & subsequently upgraded the furnace to HiEff.