Perimeter overflow systems are a critical part of any swimming pool. There are two main types of perimeter overflow systems; skimmers and gutters. Skimmers are often times the more simplistic and less expensive options as they are traditionally used for back yard or leisure-style pools. Gutters, however, can be used on any pool type and they can be constructed in an array of different shapes and sizes. Depending on the intended use for the pool, some gutters are better suited than others. The following will discuss the pros and cons of the four most common styles of gutters: deck level, fully recessed, roll-out, and parapet.
Deck Level Gutter
The deck level or "rim flow" overflow system features a gutter lip 1” above the elevation of the pool deck. This design enables even the weakest swimmer to egress with little effort over the water's edge. This is often the most desirable gutter for the recreational and instructional swimmer. Program heavy natatoriums, where many classes are taught, often choose this design option. Deck level gutters are the least expensive gutter option as they require less concrete and forming compared to some of the other options.
The deck level gutter does not have back curb, therefore, water has the potential to “run” across the gutter grating or splash-out resulting in a wet pool deck. Because the water level in the pool is typically at or above the elevation of the adjacent perimeter slabs, surge tanks often will need to be fitted with overflow piping to prevent flooding.
Fully Recessed Gutter
Competitive swimmers and coaches prefer this design. The pool deck cantilevers over the gutter trough. The top of 
deck is approximately 12” above the water. The overhang provides the competitive swimmer with a visual reference plane for the underwater wall. The recessed gutter very effectively captures the wave amplitude and keeps the pool decks relatively dry. The disadvantage is that the high overhang makes egress from the pool rather difficult, and as a result, most people choose to use one of the pool ladders. This option is often used for natatoriums where competitive swimming is the predominant programmed activity. It should be noted, however, that fully recessed gutters are typically one of the most expensive gutter options.
Roll-Out Gutter
The roll-out gutter profile combines the features of the fully recessed and deck level configurations. It consists of a gutter lip and grate at the water level. The deck, approximately 5” above the water surface, forms a curb at the rear of the gutter grate. This curb contains much of the wave action and keeps the pool deck relatively free from water escaping the gutter assembly. The low configuration at the water's edge still allows swimmers to egress easily. Unlike the fully recessed gutter however, the roll-out gutter does not provide competitive swimmers with a visual reference of the end wall above the water surface.
Roll-out Gutter with Parapet
A roll-gutter with parapet combines the roll-out gutter design on the sides of the pool with a parapet on the ends of 
the pool. The parapet is very similar to the fully recessed gutter option with a 12” water to deck dimension and a visual reference plane for the underwater wall. The parapet utilizes a 6” curb from the pool deck to top of the gutter where the starting blocks would typically be located. This option is often times used when lap swimming is the primary use, but the pool is also used for other programming activities.