What do you do if a dog you're watching has fleas?

First, I’d recommend you contact the owner, ask them what treatment they’re on because it is not working for them. Let them know what you observed.( It is completely possible that they were truthful and their dog is on a preventative that isn’t working. ) Based on what their dog was given, will direct the next step of how to treat the dog, without a toxic overdose. Ask if they would like you to take their dog to their groomer or a vet for flea dip bath, flea meds. (providing that they’re close enough to you), where they can bill them directly or take credit card information over the phone/Internet/upon return. Otherwise, you could pay for whatever they agree to & provide them a receipt when they return for the dog, which they reimburse you with cash.

At this point, now that the dog has been in your home overnight, you probably are going to have to address it anyway. Every soft surface in your home that can go into the washing machine (,bedding, etc) needs to be laundered with Hot soapy water. Floors need to be vacuumed frequently and the bag needs to be changed outside so the eggs don’t hatch in between uses.