Do an inspection of the property once a month to make sure it is working (in case they break it and don't report it).Other option is to remove it, but chances are they'd block the drain which again would be repaired at their expense.

The only rental claim I had a tenant submit for renters insurance was denied (condo flooded due to an exterior patio drain backing up) and they felt that damaged was not their liability. 

I have a lot of friends who have been hit hard by 50% rent increases and it breaks my heart to see the creative drain of folks moving away who can't afford to live in the city anymore.

First, I think it's strange that a landlord would be Facebook friends with an ex-tenants mom ;)Also, re: the OP - the next bandit sign he handwrites for the front yard is going to read " _____  PUTS CONCRETE IN DRAINS" ... and _______ won't care a single bit. 

I used to do this as a HML but with the regs the way they are its too much brain drain and overhead easier for me to simply buy the asset for my teams in situ.

We used leverage (20% to 25% down) to scale with sufficient reserves.The past two years have been hard on us personally due to myriad of reasons 1) higher turnover costs in our area possibly related to COVID and local market dynamics 2) bad section 8 tenant (not allowing anymore for our homes) --> eviction and costly repair  3) unexpected high cost repairs on few properties  - water intrusion needing french drain, plugged old sewer line needing new sewer line,  fallen tree that pulled electrical cable that pulled out the wall electrical panel.   

I know when I have owned my brokerages... the top producers were just that top producers that had little time for a flip.and why take on all that brain drain and risk for 20k when they are making 50k or more a month with ZERO risk to the bank and having to deal with contractors etc.top realtors in our market with teams will make 7 figures.. 

I had to pay $665 for the plumber to unclog the drain.

The clogged sink drain and probably AC is on them. 

If freezing is a concern, I would winterize the washer because all the water might not want to drain out.