Monday marked the beginning of a week-long greywater installation course at the Humanist Hall. The day was jokingly deemed "Laundry Day." No, not the day to throw dirty clothes in the wash. Rather, the goal was to create a basic and inexpensive system to carry excess water from your washing machine to a drum, then into your yard for irrigation.

Greywater is any used water from bathroom sinks, showers, tubs and washing machines that can be recycled and put to other uses. The group conducting the course is Greywater Action, an organization dedicated to teaching people how to conserve and reuse water "for a sustainable water culture."

Formerly called Greywater Guerrillas, the group's name had to evolve when California recently updated its Plumbing Code to decriminalize residential greywater systems. 

This week's course, which started March 1, is being led by by Laura Allen, a former elementary teacher turned greywater enthusiast and co-editor of Dam Nation: Dispatches from the Water Underground, and Andrea Lara, a plumber (and plumber's daughter).

Students have traveled from as far away as Quincy, northwest of Chico in the middle of the Sierra Nevada. Some have years of experience as builders and plumbers while others have none. But all came to acquire new knowledge and skills for landscape design, green building, plumbing or simply home use.

In the morning, students learned about greywater in the context of national and global water issues, then split into small groups to learn to build a basic greywater system.

Each group drilled a 3/4-inch hole in a 5-gallon drum, inserted and tightened a pipe thread, then checked for leaks. In an installed system, a hose would run from a washing machine to the top of a much larger barrel, then out the bottom through a hose to the site of irrigation.

For the rest of the week, the course will cover four greywater systems, site assessments, vegetation that does best with greywater and best practices for residential greywater reuse. On Friday, students can opt to take an exam and conduct a live installation to be certified and listed on Greywater Action's Web site.