While encouraging children to be part of all household activities, you can still be teaching colors to them. Family life is about being, doing and working together, helping each other and having fun doing it, regardless of the activity.
When you hang out the washing, encourage children to “help” you by handing you the pegs as you put them on the clothes line. Tell them the color of the peg as they give it to you. It won’t be long before they will be telling you each color.