The Rain Bird DB12KITB 12" Drainage Basin Kit is a complete, ready-to-install surface drainage solution designed for residential, commercial, and municipal landscapes. Whether you're addressing standing water in a lawn, managing runoff from a driveway or patio, or protecting a foundation from erosion, this kit includes every major component needed to get water moving and keep it under control. No hunting for compatible parts — Rain Bird has assembled the most commonly required pieces into one convenient package.
The kit includes a 12" square catch basin with two side outlets (DB12S2), two 3" and 4" dual-fit basin adapters (DBAA34), a basin plug (DBAAP) to seal any unused outlet, and a 12" square flat grate in black (DG12SFB). The basin itself is manufactured from High-Density Polyethylene (HDPE) — UV-stabilized to resist sun degradation — and holds a total capacity of 5.10 gallons with a 1.25-gallon sump that allows sediment to settle and minimize pipe clogging. Four screw holes are included to secure the grate firmly to the basin. The black flat grate is rated for up to 3,000 lbs of load (when basin is encased in concrete), has a 7/16" open slot width, and a 53 sq in open surface area capable of handling flow rates up to 70 GPM.
The basin also features an optional perforated outlet at the bottom that can be cut out for additional drainage or removal of standing water from the sump. The 3" and 4" adapters included connect to corrugated pipe, triple wall pipe, and PVC sewer & drain pipe. If your project requires connecting to 6" pipe, a separate 6" Basin Adapter (DBAA6) is available. Need more depth? A 12" Square Basin Riser (DBRE12) can extend the basin height by 6 inches. All Rain Bird drainage products carry a 3-year warranty — the longest in the drainage product category. These products are also Made in the USA.
Looking for the same kit with a green grate to blend into turf? DripWorks also carries the Rain Bird DB12KITG – 12" Drainage Basin Kit with Green Grate. If you need the basin or grate separately, those are also available individually in the DripWorks Drainage category.
| Part Number | Component | Qty | Description |
|---|---|---|---|
| DB12S2 | 12" Square Catch Basin – 2 Outlets | 1 | HDPE, UV-stabilized; 5.10 gal capacity, 1.25 gal sump; optional perforated bottom outlet; 4 grate screw holes |
| DBAA34 | 3" & 4" Basin Adapter | 2 | Connects basin outlets to 3" or 4" corrugated pipe, triple wall pipe, and S&D pipe |
| DBAAP | Basin Plug | 1 | Seals any unused side outlet on 9", 12" & 18" square basins |
| DG12SFB | 12" Square Flat Drainage Grate – Black | 1 | HDPE, UV-stabilized; 53 sq in open area; 70 GPM max flow; 3,000 lb load rated; ADA compliant; anti-skid textured surface |
| Specification | Details |
|---|---|
| SKU (DripWorks) | RBDB12KITB |
| MPN (Rain Bird) | DB12KITB |
| Basin Size | 12" Square |
| Number of Outlets | 2 side outlets + 1 optional perforated bottom outlet |
| Basin Material | High-Density Polyethylene (HDPE), UV Stabilized |
| Basin Total Capacity | 5.10 gallons |
| Sump Capacity | 1.25 gallons |
| Grate Size & Shape | 12" Square, Flat |
| Grate Color | Black |
| Grate Material | Structurally Foamed HDPE, UV Stabilized |
| Grate Open Slot Width | 7/16" |
| Grate Open Surface Area | 53 sq in |
| Maximum Flow Rating (Grate) | 70 GPM |
| Maximum Load Rating (Grate) | 3,000 lbs (basin encased in concrete, load uniformly applied) |
| ADA Compliant | Yes (flat grate) |
| Adapter Pipe Compatibility | 3" or 4" Corrugated Pipe, Triple Wall Pipe, S&D Pipe (ASTM D2729) |
| Optional Riser Extension | DBRE12 – extends basin height +6" |
| Origin | Made in the USA |
| Warranty | 3 Years (Rain Bird) |
| Brand | Rain Bird |
| Parameter | Value |
|---|---|
| Open Slot Width | 7/16" |
| Open Surface Area | 53 sq in |
| Maximum Flow Rating | 70 GPM |
| Maximum Load Rating | 3,000 lbs |
| ADA Compliant | Yes |
| Anti-Skid Surface | Yes (textured) |
| Compatible Basins | DB12S2, DB12S4, DB12SLP |
What pipe sizes does this kit connect to?
The two included DBAA34 adapters each fit 3" or 4" corrugated pipe, triple wall pipe, and sewer & drain (S&D) pipe (ASTM D2729). If you need to connect to 6" PVC or 6" corrugated pipe, you can purchase the separate 6" Basin Adapter (DBAA6) to use with the included DB12S2 basin.
Can the basin be made deeper?
Yes. The Rain Bird DBRE12 12" Square Basin Riser extends the height of this basin by 6 inches. Multiple risers can be stacked if additional depth is needed for your installation.
Is the grate rated for vehicle traffic?
The 12" square flat grate (DG12SFB) is load-rated for autos and light trucks at speeds less than 20 mph and carries a maximum load rating of 3,000 lbs — but this rating applies only when the basin is fully encased in concrete with load uniformly applied across the entire grate surface. For pedestrian-only applications, standard installation in soil or gravel is sufficient.
Is this grate ADA compliant?
Yes. The flat grate profile and 7/16" slot width meet ADA requirements for surface accessibility.
Can I use only one of the outlets?
Absolutely. The included basin plug (DBAAP) is designed to seal off any unused side outlet. Simply cap the outlet you don't need during installation.
Does the basin have a sediment trap?
Yes. The DB12S2 basin includes a built-in sump (1.25 gallon capacity) at the bottom that allows sediment, debris, and grit to settle before water exits through the side outlets. This significantly reduces clogging in downstream pipes and reduces maintenance frequency.
What is the difference between the black grate kit (DB12KITB) and the green grate kit (DB12KITG)?
The kits are identical in all functional components — basin, adapters, and plug — and differ only in grate color. The black grate (DG12SFB) blends well with dark hardscape, gravel, or mulch areas, while the green grate version (DB12KITG) is designed to blend into turf and lawn areas.
How do I secure the grate to the basin?
The DB12S2 basin includes four screw holes to allow the grate to be secured. Rain Bird recommends using #6, 1.5" Phillips flat head stainless steel screws (not included) for a rust-free connection.
Is there an optional bottom outlet on the basin?
Yes. The basin bottom has perforated knock-outs that can be cut out — one larger optional outlet for additional pipe connection, plus four small drainage holes that can be opened to remove any standing water that accumulates in the sump.
What warranty does this product carry?
All Rain Bird drainage products — including this kit — are warranted to the trade for 3 years from the date of original purchase. This is the longest warranty offered in the drainage product category. Rain Bird will repair or replace any product that fails under normal use within that period.
Before you install, confirm the following:
Pair this basin kit with other Rain Bird drainage components available at DripWorks:
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