Indoor plumbing was first developed in Monab in the 890s, by Lyle. The technology was later introduced in the Northern Alliance, in 897. In 901, plumbers and engineers from the Northern Alliance began introducing these designs to other villages. The most notable use of indoor plumbing is water closets, which have now largely replaced outhouses throughout The Land. However, plumbing is also now commonly used in kitchens and laundry rooms, making cooking and cleaning, as well as the simple act of getting a cup of water, much quicker and easier, and eliminated the need for leaving the house to perform such basic tasks.
Plumbing utilizes a system of pipes, piston pumps, valves, filters, and other parts, which serve to bring water into homes and other buildings, as well as to transport used water and various waste products to sewers. (Water comes in through sinks, tubs, and toilets, and is subsequently disposed of down drains in the same fixtures.) Along with the plumbing itself, treatment facilities have been built to sanitize water from sewers, rather than relying entirely upon the environment itself to purify waste. There are also facilities that collect water from both natural sources such as rivers, and treatment facilities, to transport water into homes via the plumbing infrastructure. An innovation of engineers in the northern villages was to install stoves in the water closets, which can channel heat into the pipes that bring the water to the tub.
The introduction of plumbing served as one of the earliest elements of The Plan, which led to the Coming of the Order.