Pool glossary
At a glance: This glossary defines 29 pool building, permit and safety terms as they are used in San Diego County, from baja shelf and bond beam to SVRS and zero edge, each linked to the article where it matters[1][2].
Which pool terms does this glossary define?
The definitions below are written for this reference and link to the article where each term is used. They draw on the City of San Diego’s pool bulletin, County form PDS-379, California’s pool safety law, CSLB guidance and the company’s own materials[1][2][3][4].
- Baja shelf
- A shallow ledge, a few inches deep, for lounging or children; also called a tanning ledge or sun shelf. See Pool styles and video library.
- Bond beam
- The thickened top of a concrete pool wall that supports the coping. In the City of San Diego its height counts toward the soil a master plan pool retains. See Master plan or custom pool.
- C-53
- The California contractor license classification for swimming pool contractors. See License and credentials.
- Cascade
- A stream of water spilling from a raised element, such as a spa or wall, into the pool. See Pool styles and video library.
- Catch basin
- The trough below a vanishing or zero edge that collects the overflowing water before it is pumped back. See Pool styles and video library.
- Coping
- The cap along the top edge of the pool wall, between the waterline tile and the deck. See How a shotcrete pool is built.
- Custom pool
- In the City of San Diego, any pool that does not meet all the conditions of a registered master plan. See Master plan or custom pool.
- Dual drains
- Two suction outlets at least 3 feet apart, piped together so that blocking one cannot trap a swimmer. See Drain entrapment safety.
- Enclosure
- A fence, wall or other barrier that prevents access to the pool from neighbouring properties, and possibly from the home. See Pool safety barriers.
- Exit alarm
- An alarm on a door or window that opens directly to the pool, sounding when it is opened. See Pool safety barriers.
- Geotechnical report
- A soils engineer’s report on ground conditions, required for some pools in difficult soils or with high retaining walls. See Pool permits in San Diego.
- Gunite
- Dry-mix sprayed concrete: dry material is blown through a hose and water is added at the nozzle. See How a shotcrete pool is built.
- Heat pump
- An electric heater that moves heat from the air into the pool water; a compliant primary heat source for new pools in California. See Equipment and energy rules.
- HIS registration
- Home improvement salesperson registration with CSLB, needed by salespeople who sell pool contracts away from the contractor’s office. See Hiring a pool contractor.
- Master plan pool
- In the City of San Diego, a pool built exactly to a pre-approved, registered design, permitted faster than a custom pool. See Master plan or custom pool.
- Mastic
- The flexible sealant in the expansion joint between the coping and the deck. See Warranty and service.
- Pebble finish
- An interior finish of small aggregate stones set in cement, more textured than plaster. See How a shotcrete pool is built.
- Plaster
- The traditional cement-based interior finish of a concrete pool; white plaster is the standard finish in many packages. See How a shotcrete pool is built.
- Raised spa
- A spa set above the pool level, often spilling into the pool. See Pool styles and video library.
- Rim flow (wet edge)
- A pool where water flows over the whole perimeter or a wall, so the surface sits level with the deck. See Pool styles and video library.
- RMO
- Responsible Managing Officer: the officer who qualifies a corporation for its contractor license classification. See People.
- Safety pool cover
- A manual or powered cover meeting ASTM F1346; it can count as one of the state’s drowning-prevention features. See Pool safety barriers.
- Setback
- The minimum distance between a pool or its equipment and the property lines. See Pool permits in San Diego.
- Shotcrete
- Concrete or mortar sprayed pneumatically through a hose; in pool building usually the wet-mix process. See How a shotcrete pool is built.
- Spool
- A small combined pool and spa. See Pool styles and video library.
- SVRS
- Safety vacuum release system: a device that detects a blocked suction line and releases the vacuum. See Drain entrapment safety.
- Variable-speed pump
- A pump whose motor can run at many speeds, saving energy by filtering at low speed. See Equipment and energy rules.
- Waterline tile
- The band of tile at the water surface, which resists staining better than plaster. See How a shotcrete pool is built.
- Zero edge (vanishing or infinity edge)
- An edge where water spills over into a catch basin, so the surface seems to extend to the view. See Pool styles and video library.
Does San Diego Pools publish its own glossary?
Yes. The company’s Pool Terminology page is a long glossary of pool construction and equipment terms[5]. It is a useful companion to this one, which concentrates on the terms that matter for permits, safety rules and contracts in San Diego County.
Which terms are most often confused?
Three pairs cause the most confusion. Shotcrete and gunite are both sprayed concrete, but in pool construction shotcrete usually means wet mix and gunite dry mix. Zero edge and rim flow both spill water over an edge; a zero edge usually means one side spilling toward a view, and rim flow the whole perimeter. And a master plan pool is a permit category in the City of San Diego, not a style: a master plan pool can be freeform or linear, as long as it meets the plan’s conditions.
Which terms have legal definitions?
Several terms are defined in law. For California’s pool safety rules, a swimming pool is any structure for swimming or recreational bathing with water more than 18 inches deep[6]. County form PDS-379 defines an enclosure and an approved safety pool cover[2]. CSLB defines the C-53 classification[7]. Where a legal definition exists, it governs over the plain-language versions above.
Questions readers ask
What is a spool?
A small combined pool and spa.
What is coping on a pool?
The cap along the top edge of the pool wall, between the waterline tile and the deck.
What is a baja shelf?
A shallow lounging ledge a few inches deep, also called a tanning ledge.
Related articles
Notes and sources
- ^ a b Information Bulletin 712: Swimming Pools and Spas (June 2021). City of San Diego Development Services Department. Retrieved 9 November 2026.
- ^ a b c PDS-379: Swimming Pool and Spa Safety Requirements. County of San Diego Planning & Development Services. Retrieved 9 November 2026.
- ^ Health and Safety Code section 115922 (drowning prevention safety features). California Legislative Information. Retrieved 9 November 2026.
- ^ Swimming Pool Construction: Selecting a Contractor. Contractors State License Board. Retrieved 9 November 2026.
- ^ Pool Terminology. San Diego Pools (sandiegopools.com). Retrieved 9 November 2026.
- ^ Health and Safety Code section 115921 (definitions). California Legislative Information. Retrieved 9 November 2026.
- ^ C-53 Swimming Pool Contractor classification. Contractors State License Board. Retrieved 9 November 2026.