My yellow females loves to play in the water hose, but it turns her chest a reddish/brown, this is only in the chest area, the rest of her body is fine. We are on county water/not well water. Maybe what they might add to the water is doing this ? Some type of a fungus from the moisture ? She plays in the water daily year round, she loves the water. Has anyone seen this,or any clues
as to what is causing the color change. When I keep her out of the water it does go away.

Have you noticed that after she's in the water that she is licking herself? I have noticed that if you don't dry them off, they lick themselves dry and over time it will discolor

I have never notice her licking herself in that area after water play, actually she seems to play and just air dries. My other yellows don't get this discoloration after water play.

Get some malacetic spray (pump bottle) from your vet and spray that area. Once you get rid of it your good, it won't go away on it's own. It's caused from too much moisture that doesn't get fully dry.