-Negligence.

Divide that by 12 months and you're talking $1 per month per toilet...if they double flush every single time.I would tell the renter to study their water bills and they'll see the increase is negligible.

There's no way these sorts of things should be happening after 16 years of owner-occupancy, however negligent the tenant may argue that you were on regular maintenance when you lived there.

It happens all the time.The risk of loss is usually for negligence.

No personal assets are subject to loss unless gross negligence was present.Hope this helps some.

I believe she took advantage of my remoteness and newness to suggest unfair profit sharing arrangements, has knowingly and repeatedly engaged in a pattern of hiring incompetent (and possibly outright fraudulent) contractors and performing unsafe and dangerous alterations to her flips, and is both negligent and incompetent at supervising renovation projects.

Their supposed negligence put you in this situation.

I think this issue falls on the builder due to negligence. 

@Richard Helppie-SchmiederIf I were the tenant I would want to know what actions my Landlord is taking to resolve the issue but I definitely wouldn't ask my Landlord to reduce rent for an inconvenience unless it was due to their negligence. 

If she mentions lawsuit, feel free to say something like "Due to the minor damage, I probably won't be suing your mother for her lighting a fire and her subsequent negligence in failing to watch over it."