As was stated on 4/7, if Soresto works by spreading through the dogs fur or hair, it makes sense that it would be washed out if the dog frequently gets in water. However, we have washed our dogs every 7-10 days (always removing the collar) and have not had a problem at all with fleas or ticks and we live in a very tick prone forest.
The finding that very little of the active tick killing chemical is absorbed in the blood stream is the most important factor to me. (Though if your dog will be frequently in water, I agree that Soresto is likely not appropriate.)
Rich Beaudry
Date: Wed, 8 Apr 2020 11:59:22 -0400
From: Rich Beaudry
Subject: Re: Soresto flea and tick collars