Well you don't need it... Holey jeans with a t-shirt, or a white tank top and running shorts are fine for doing homemaker-y things.
But having a fun uniform sure makes things more fun. Here are some suggestions for articles of clothing that are great for a day of laundry, working in the garden, cooking some excellent food, or even just kicking butt and taking names.
Item #1: The American Shirtdress
My raspberry American Shirtdress was the best 50 cents I ever spent. I got it for 50 cents at a yard sale. It's great for a morning in the garden, or cooking and cleaning. Add sneakers, and you can go power-walking. Add heels and pearls, and you feel like Betty Draper.
Item #2: Overalls
My overalls were free. Some foolish person was giving them away. They have been faithful companions as I do battle with thistles and poison ivy in the garden, built a stage for a music festival, baked pies, done things with my horses, and taken finals. Don't spend much money on a pair of overalls. I found the perfect pair of overalls when I wasn't even looking. It may take months and months, but if you build it, they will come.
Item #3: A Blue Jean Skirt
This is the least obscure item on the list. I slip on my blue jean skirt with a t-shirt because sometimes I have things to get done, but I just don't want to wear pants. This is also good if you don't like the American Shirtdress, or haven't found the perfect one for you yet. A blue jean skirt is casual yet classy if the right length. It can take you from cleaning to clubbing with a change of shoes, shirt and jewelry. Plus, if you can't find one that is the length you want, you can make one yourself. But that's for another blogpost.
Extra Credit: A Bandana
Whether you wear it like a peasant, a pirate, or Rosie the Riveteer, bandanas are great for days when there's no point in washing your hair because you're just going to get it dirtier anyway.
Happy housewife-ing!