There are certainly no hard-and-fast rules that predict exactly how plumbing will be laid out in a building. Older buildings, especially those with additions made after the initial construction, may have a very complicated plumbing layout. However, in new home construction, there are some basic guidelines that most contractors follow that makes plumbing installation more affordable and less complicated.
Whenever possible, building designers like to simplify the location of plumbing in the building. For instance, it makes more sense to have bathrooms on separate floors located relatively close to above one another instead of locating them in the opposite corners of the house. Obviously this is not always possible, but when it is, it greatly simplifies lines running away away from the main water supply and drainage lines, because the pipes can run through the same interior wall.
Typical plumbing layouts on single floors also include shared walls whenever possible. This means designing fixtures so two bathrooms might share a common wall between them, or a bathroom might share a wall with a kitchen. This allows plumbing to serve both rooms from a single wall, requiring less plumbing infrastructure and less time to install the plumbing.
Many elements of residential plumbing are dictated by locally applicable building codes. Things like the slope of a drain or the permitted location for drain pipes are all typically laid out in building codes. Therefore, certain design elements will be typical for all homes in a given region, based on the applicable local codes. Before designing any of the plumbing layout that you intend for your home, always check with the local building authorities, so you don't plan anything that won't pass inspection once you start on the project.
Again, while not a hard-and-fast rule, it is typical to find many of the plumbing fixtures located on the same side of the building as the source of the main utility lines. If the kitchen counter, laundry room, bathroom and hot water heater are located on the side of the building where the supply line enters the house and the drain pulls waste away to the sewer, the overall plumbing arrangement requires fewer pipes.
- Photo Credit Comstock/Comstock/Getty Images