I am confident you’re not going to figure out what this is. But I hope you can prove me wrong.

The laundry water would be carried by hand, warmed over a fire to facilitate washing, and then transferred into a tub.

This meant that only a certain amount of warm, soapy water could be used; it would be used to wash progressively dirtier laundry after the least dirty clothes were cleaned.
Hand laundry entails soaking, pounding, cleaning, and rinsing soiled fabrics. All of the water needed for laundry washing, boiling, and rinsing had to be carried from a pump, well, or spring prior to indoor plumbing. Carrying water by hand, heating it over a fire to wash, and then pouring it into a tub would be the laundry process. This meant that only a certain amount of warm, soapy water could be used; it would be used to wash progressively dirtier laundry after the least dirty clothes were cleaned.

After washing, there was another step involved in getting the soap and water out of the clothes. First, clear water would be used to rinse the soap. The drenched clothes would be rolled up and manually twisted to remove the water after washing. When drying and ironing were added, the entire procedure frequently took a full workday.