Washing Eurasier

Hi, So I’ve understood that you shouldn’t shower dogs and Eurasier in particular too often, like every 3 months or so because it’s not good for their fur and skin. But now that the weather is rainy and muddy my puppy gets dirty almost every time he goes out as he rolls around in the leafs and when we get home he’s a bit muddy on his belly, feet and so and I can only get him clean by washing him with water?

What do you guys do? Or is it only washing with shampoo and conditioner that you should do less often like every 3 months or so?