Use borax powder or boric acid baits for cockroach extermination and electric trap for mice control.

Is it borax, or boric acid?

Active enzyme killer, Clorox , Sodium carbonate peroxyhydrate , Muriatic acid then a sealer.

For insurance, the tenants property is covered as personal property on premises, you property is under your coverage as property away from your premises or under your landlord policy as on premises, coverage amounts are different for these classifications.My lease also addressed personal property and substances kept on premises, restricting flammable, toxic, acidic or corrosive materials not normally found for or in residential properties and that common materials are stored in proper containers.

Then acid wash and seal the concrete foundation.

Without knowing if your water is good quality - acidic or neutral, high iron, etc - and the fact that it serves 20 units, I would probably start planning to replace it.

You'll have to replace the carpet, carpet padding, and acid wash the concrete underneath.Cats can easily DESTROY carpets, windows (scratching), curtains and drapes, doors, and so on with their scratching.

By some hardcore ( almost pure sulfuric acid) drain cleaner...use every time a tenant moves out....and dont get it on you.

I empty the water from the toilet bowls, pour muriatic acid in the bowls, use rubber gloves, Comet powder or some other brand and I make the worse-looking toilets in about 10 minutes and make them look like they just cake out of the box.

If its well water , and the water is acidic , and you have copper pipes , you will get bluish stains in the sink , tub and toilet .