It's time to clean your washing machine! Even if it's not visibly dirty and grungy, this will help clean soap scum and mineral deposits in the pipes and hoses. You just need vinegar, bleach, and two wash cycles!
"Greywater" is water that comes from your sink, shower, bathtub or washing machine. It's not drinkable, but it's still usable. You can water plants with it, or even install a "greywater system" to filter and reuse the water in your toilet tank.