What Plumbing Designers Need to Know About Selecting a Lavatory

Discover which factors to take into account to make an informed decision that suits the needs of the client and the users.

by Siddharth Bhat, PE, CPD, GPD, LEED AP, WELL AP 

Following a bit of a break, let’s resume our series on selecting plumbing fixtures and move on to the next stop: lavatories. Lavatories are present in some form or other in the majority of buildings. This article provides a checklist of features and parameters to consider when selecting lavatories for your projects.

Type of Bowl

A number of installation options are available for lavatories. The most common among them are wall-hung, integral, pedestal, self-rimming, and vessel type.

Wall Hung

Wall-hung lavatories, as the name suggests, are installed on the wall. The units come with carriers that allow for them to be hung. Leg guards are common for wall-hung units. These allow for the concealment of pipes, thus adding to the aesthetics of the space.


Integral-type lavatories have bowls integral to the countertop. Many times the countertop is specified by the architect, while the plumbing designer specifies the bowl. In such circumstances it is imperative to coordinate the bowl type, color, shape, etc., with the architect to ensure that the desired aesthetics are maintained in the space.


Pedestal lavatories are freestanding, single-piece lavatories. Some owners may prefer these since all of the plumbing pipes are concealed, thus maintaining the aesthetics of the space. Due to its shape, the pedestal lavatory is easy to clean and maintain, which is another reason they may be preferred in certain cases.


Self-rimming lavatories are similar to drop-in or top-mounted sinks. These are installed on the top of the countertop, with the rim resting on the countertop. The benefit of this type of lavatory over the integral type is that while integral-type units are undermount and require supports for the bowl, the rim of the integral-type bowl rests on the countertop; thus, it does not require any special supports. However, the disadvantage as compared to the integral type is that, since these units are mounted on top of the countertop, dust and other contaminants may accumulate in the gap between the bowl and the countertop, making it difficult to maintain sufficient hygiene at times.


Vessel-type lavatories are similar to the self-rimming lavatory, but the key difference is that instead of being mounted in the countertop, they rest on top of the countertop. The most important benefit of this sink is the ability of it to be changed. Since the sink just rests on the countertop, it makes it easier to select a different model as required. It also has similar benefits to the self-rimming sink, as in the requirement for less support, but it’s easier to clean than the self-rimming lavatory as there are limited spaces where contaminants can accumulate.

Bowl Shape

Bowls are available in multiple shapes such as oval, round, rectangle, and square. Some manufacturers also provide custom shapes as needed, although these may be costlier than regular units. Bowl shapes are typically coordinated with the architect to maintain the proper aesthetics in the space.

The color of the bowl is an important consideration as well. Manufacturers have multiple color palettes available, both standard and custom. The color also needs to be coordinated with the architect, especially for integral, self-rimming, and vessel-type units.


Once the bowl is selected, you need to focus on the faucet. The following factors need to be considered when selecting a faucet:

  • Faucet spout reach
  • Number of holes required for faucet installation
  • Mode of operation (manual vs. battery vs. hardwired)
  • Aesthetics

Faucet Spout Reach

Faucet spout reach is the most important factor when selecting a faucet. It is the distance from where the spout is located to where the water lands in the bowl. Ideally, the reach should be such that water lands close to the lavatory drain to avoid unnecessary splashes around the bowl. However, too low of a reach would make it difficult ergonomically for users to wash their hands and would involve excessive bending (which may be even more critical for users with Americans with Disabilities Act [ADA] needs). On the other hand, too high of a reach would mean that water may splash out of the bowl, thus affecting hygiene in the nearby area.

Number of Installation Holes

Another important item to consider is the relation between the number of holes in the bowl and the number of holes required for faucet installation. Faucets typically are available in a single-hole or three-hole option. Three-hole faucets are typically available with holes 4 inches on center or 8 inches on center. It is critical that the number of holes on the bowl (and the span of holes) match the faucet that has been selected. If the number of holes on the bowl is larger than the number of holes on the faucet, you may need to use a cover plate to conceal the additional holes to maintain aesthetics as well as reduce points of contamination. On the other hand, having a lesser number of holes or improper span would require drilling additional holes in the countertop. This in turn leads to possible improper work quality in the field and a negative impact on the aesthetics of the fixture.

Operation Mode

The mode of operation is the type of power source needed for operating the faucet. Faucets may be manual or automatic. There have been multiple advances in the field of automatic faucets, especially since the pandemic. Some faucets have a pushbutton to change the water outlet flow from the faucet. Water may come out as a spray or a stream, thus allowing users the flexibility to determine the flow. Some manufacturers provide a voice function to turn the faucet on and off. Other faucets are activated and deactivated via touch. Automatic faucets reduce the number of touch and contamination points on the faucets, thus assisting in improving overall hygiene.

Automatic faucets are available as battery powered or hardwired. Hardwired faucets derive power from a nearby panel circuit, and transformers are provided with the faucet. This is sometimes preferred by clients over battery-powered units since labor and the expense associated with battery replacement during the operational phase of the building are reduced. However, due to recent advances, many commercially available units have a longer battery life or number of cycles, which has moved some owners toward battery-operated fixtures. These fixtures also assist in reducing the initial cost of the project since no special circuitry is required.


Faucets also are available in multiple shapes, which makes it critical to coordinate with the architect. Some manufacturers provide multiple selection features such as online configurators where you can select different faucets and visualize how they appear in real life. Other manufacturers provide the entire setup as a single system including the bowl, faucet, carriers, stoppers, drains, etc. The benefit of this is that you can visualize how an entire system looks, and it reduces the chance of any mistakes since the entire system comes as a single design package ready to be installed. This may also assist in reducing the cost of installation in the field, reducing the initial cost of the product, and increasing manufacturer warranties in certain cases.

Other Features to Consider

ADA requirements are common features to consider in spaces requiring ADA compliance. This information is typically listed in the manufacturer’s specifications.

An environmental product declaration (EPD) may need to be considered especially if the owner is aiming for wellness rating systems such as LEED and WELL. EPDs indicate the overall sustainability of products as part of life-cycle assessments as compared to the baseline. For LEED, depending on the categories being pursued, you may need to consider health product declarations (HPDs) as well. Most of the time these compliances are listed under the manufacturer’s specifications. If the owner is opting for compliance to other green building ratings such as BREEAM or BAA, you may need to coordinate the same with the manufacturer. Regulatory requirements such as carbon neutral, etc., also need to be taken into account.

In conclusion, lavatories have gone through multiple advancements over the years. Designers need to take all of these factors into account along with budgetary constraints to make an informed decision that suits the needs of the client and the users.

About the Author

Siddharth Bhat, PE, CPD, GPD, LEED AP, WELL AP, is a Mechanical and Plumbing Engineer with specialization in correctional facility design.

The opinions expressed in this article are those of the author and not the American Society of Plumbing Engineers.

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