How should I treat fleas when caring for someone else's dog?

Please advise the owner’s that per Rover Guarantee does not cover fleas so this would be at the owner’s expense and responsibility. Any means of Rover Sitter can be held legally liable for damages (per Rover Representative and On-Call Service). Contact Rover and owner.

You’ve already started down the right path, of alerting the owners to the issue and sending photos to document. The rest of what I would usually suggest may not be applicable to these owners because you’ve seen that this is a long standing problem that they have not been addressing

There are holistic ways to deal with fleas, which can be used for dogs with sensitivities or are on preventative. One of the recommended methods is to get a flea comb, which is dipped in a warm sudsy solution in between each stroke over the entire body, to remove all fleas after coming in from outside.

Some people spray a diluted/watered down apple cider vinegar, but due to the bleeding, I would not recommend that because it’s very acidic. Same applies to a flea dip bath due to the bleeding, I would not suggest that..

Wherever these dogs are staying (Your or their home?) needs action to eliminate fleas and flea eggs.If these dogs are staying at your home, you’re going to need to launder every soft surface (dog beds, throw rugs, curtain,towels, sheets, etc) in hot sudsy watering vacuum often (each time removing bag outside and disposing to prevent hatching inside). If the dogs are staying at their home, you might want to suggest and see if they want to hire someone to do it

The owners can get flea/tick preventative at the vet so this doesn’t keep happening. However, it sounds like they need to be seen by a vet anyway to rid the current fleas and bleeding from the itching (former vet tech—holistic stuff doesn’t treat fleas), but it doesn’t sound like they are too keen on treating or preventing it from what you’ve said.

Honestly, if they ask you to sit again, I would ask if the flea situation is better because you care about the pets before you sit for them again. I’m so sorry you have to witness these dogs suffer as much as they are. I know this doesn't provide too much if a solution, but I hope it helps some.

Bathing with dawn dish soap from the neck down will help with the fleas that are on them until the medicine arrives. If you are able to also vacuum any carpets and wash pet bedding, that will help kill fleas in the environment.