Rain Bird 12" Square Drainage Catch Basin, 2 Outlets

DB12S2 – 12" Square Catch Basin Specifications

What is a catch basin, and where should I install one?
A catch basin (also called a storm drain or yard drain) is an underground collection point for surface water runoff. It captures water through a grated top opening and routes it away via underground pipe. Install one at any low point in your yard where water naturally pools — near downspouts, at the base of a slope, in the corner of a driveway, along a patio edge, or at the low end of a swale. The DB12S2 is ideal for residential yards, driveways, and commercial landscaping projects where a 12" square footprint fits the application.

What pipe sizes does this basin connect to?
The DB12S2 connects to 3" and 4" pipe (corrugated, triple wall, or sewer & drain) using the Rain Bird DBAA34 Basin Adapter, and to 6" pipe (corrugated or PVC meeting ASTM D2729, D3034, SDR 35) using the Rain Bird DBAA6 Basin Adapter. Adapters are sold separately. Use a Basin Plug (DBAAP) to close off any outlet that is not connected to a pipe.

Does this basin come with a grate?
No — the DB12S2 is the basin body only. It is designed to accept 12" Square Flat Grates and 12" Square Atrium Grates, both sold separately. The atrium-style grate is recommended in areas with heavy leaf or debris load, as its taller design allows water to enter even when the grate top is partially covered. The flat grate is ideal for high-traffic or flush-to-grade installations.

What does the sump do, and why does it matter?
The sump is a recessed area at the bottom of the basin that sits below the outlet pipes. As water flows in and slows down, sediment, sand, and debris settle into the sump rather than being carried downstream into your drain lines. This significantly reduces clogging and extends the service life of your underground pipe system. The DB12S2 sump holds 1.25 gallons. Clean the sump periodically — especially after heavy storms — by removing the grate and flushing or scooping out collected sediment.

Can I raise this basin to match my finished grade?
Yes. The DB12S2 accepts 12" Square Basin Risers, each of which adds 6" of height. This is useful when you need to set the basin lower during initial installation and then bring it up to grade after grading or landscaping is complete, or when installing in areas where grade may shift over time.

How many outlets does this basin have?
The DB12S2 has two side outlets as standard, plus one optional bottom outlet that can be opened by cutting along the perforations. There are also four small perforated drainage holes on the basin floor that can be cut out to allow standing water in the sump to slowly percolate into the surrounding soil. This makes it adaptable to both piped drainage systems and partially infiltrating installations.

Is this basin UV-resistant for above-ground or exposed installations?
Yes. The HDPE material is UV-stabilized to resist degradation from sun exposure. While basins are typically installed flush to grade or partially below grade, the UV stabilization ensures the material won't become brittle or crack if sections are exposed to sunlight during or after installation.

What is the difference between the DB12S2 and a channel/trench drain?
A catch basin like the DB12S2 is a point drain — it collects water from one concentrated location and routes it through underground pipe. A channel drain (trench drain) is a linear drain that collects water along its entire length and is best for long runs where water sheets across a surface. For most residential applications — pooling near a downspout, at the low corner of a yard, or at the end of a swale — a catch basin is the right choice. For driveways, patio edges, or pool decks where water moves in a sheet, a channel drain may be more appropriate. Browse the full DripWorks Drainage Category to compare options.