Some plumbers have a sewer cam that has a radio in it, where they can walk above on the grass with a special receiver and it will beep like a metal detector.They simply spray paint the lawn where to pipe is.Accuracy seems good with this.They can also blow smoke down the pipes and see where it leaks out.If the tank is under the structure maybe you can just disconnect it and put new one in where you can get at it.Good Luck!

No air quality test yet but that may be a good idea.A few years ago, used a spray gun to paint a room, refinished a table and sanded steps.   

The answers to dog barking, leaves falling, parked cars, surveillance cameras, cutting down trees, paint spray on new car, paint peeling, loose boards in fence, dog barking, etc aren’t the answer.  

They change Hvac filters, do pest spraying so I canceled the Pest Provider and they are rewarded instead.

It might be insulating the pipes near that trouble area, sealing drafts from the outside with caulk and spray foam, or even using heat tape to keep pipes from freezing.

Bleach the tub and tile, paint the radiator white with oil based enamel spray paint

Take a look at this:  "It is normal for roaches to come out once they spray and for two weeks, you will see lots of them but don't be afraid.

Spray on an enzymatic neutralizer of your choice (I use natures miracle just make sure it says enzymatic on it), lay plastic down so it soaks into the floor completely and doesn’t just evaporate, then you’re looking at some serious ozonation time.

You have to create hand-crafted mailers for apartment buildings if you aren't just doing spray and pray and hoping for one response.

No bad experience to report, they where key in helping solve a bed bug problem I would have struggled with (the tenant stayed through the "spraying" process).