The NDS Flo-Well is a manufactured, gravel-free plastic dry well for stormwater and downspout runoff. It collects water, holds it, and lets it soak into the surrounding soil, so the yard stops flooding without a pit full of heavy stone. Because the interior is open, NDS rates it at 250% more detention volume than a gravel dry well of the same size.
Flo-Well Specifications
| Part number | FWAS24 |
|---|---|
| Kit contents | 3 interlocking side panels + 1 cover |
| Size | 24 in. diameter x 24 in. tall; 28-3/4 in. with cover |
| Capacity | About 50 gallons per unit |
| Infiltration | Thirty 1 in. knockout weep holes |
| Weight | 19 lb |
| Material | HDPE with UV inhibitors, made in the USA |
| Expansion | Connect in series, or stack up to 4 units |
Specifications: NDS Flo-Well Dry Well (manufacturer product page and technical documents), checked September 2026.
How the Flo-Well Dry Well Works
A downspout, catch basin or French drain carries water to the Flo-Well. The unit fills, then releases the water slowly through its weep holes into the soil around it. Ribbed side panels keep it strong without gravel inside. A filter fabric wrap keeps soil out, and an optional bottom panel prevents erosion or supports a sump pump.
How to Install a Flo-Well
- Dig a hole large enough for the unit plus backfill.
- Snap the 3 side panels together and punch out the weep holes you need with a hammer.
- Wrap the unit in filter fabric.
- Set the unit, connect the inlet pipe and attach the cover.
- Backfill. For more capacity, place additional units 18 in. apart or stack up to 4 high (with a bottom panel and a center support pipe).
Plan the number of units with the NDS Flo-Well calculator.
Video: NDS, "How to Install NDS FloWell Dry Well Drainage System."
Where to Use It
- Downspouts with no downhill outlet
- Low spots and flooding areas in yards
- Playgrounds and golf courses
- Wash-down areas
Shipping
Orders over $2,000 ship free by common carrier. Most orders ship within 4 business days and arrive in 3 to 6 business days. Smaller orders ship for $40 per kit.
Flo-Well Price & Cost
Each Flo-Well kit is $115.87 and holds about 50 gallons. Shipping is $40 per kit, and orders over $2,000 (18 or more kits) ship free.
| Kits | Storage (about) | Delivered price |
|---|---|---|
| 1 | 50 gal | $155.87 |
| 2 | 100 gal | $311.74 |
| 4 | 200 gal | $623.48 |
| 18 | 900 gal | $2,085.66 (free shipping) |
Filter fabric, a bottom panel and a surface inlet are separate NDS accessories. Use the NDS Flo-Well calculator to size the system for your drainage area and soil.
Ordering 20 or more kits?
For subdivisions, commercial sites and municipal projects, request a quote with your delivery ZIP code. We quote freight and delivery to your site, and tax-exempt orders are welcome.
Complete the System
- NDS EZ-Flow gravel-free French drain: carries water across the yard to the dry well. NDS notes EZflow or drain rock around the Flo-Well adds storage (up to 40% void space) where there is no vehicle traffic.
- 12 in. catch basin 4-pack and 9 in. catch basin 4-pack: collect surface water from low spots and send it to the dry well.
- NDS 864 Pro Series channel drain: catches runoff across driveways and patios.
Downloads & Resources
- Flo-Well installation manual (NDS, PDF)
- Flo-Well frequently asked questions (NDS, PDF)
- NDS Flo-Well calculator
- What is a dry well? (NDS article)
Frequently Asked Questions
How much water does a Flo-Well dry well hold?
Each Flo-Well holds about 50 gallons. Connect units in series or stack up to 4 high for more storage.
How many Flo-Well dry wells do I need?
It depends on the drainage area, surface material, backfill and soil. NDS provides a free Flo-Well calculator.
Do you fill a Flo-Well dry well with gravel?
No. The ribbed side panels are strong enough on their own, so the interior stays open. That gives 250% more detention volume than a gravel dry well of the same size, per NDS.
How do I install a Flo-Well dry well?
Dig the hole, assemble the 3 side panels, punch out the weep holes you need, wrap the unit in filter fabric, set it, connect the inlet pipe, add the cover and backfill. Space multiple units 18 in. apart.
Can a Flo-Well go under a driveway or lawn traffic?
Bury it at least 8 in. deep. At that depth NDS rates it for light vehicular traffic (loads up to 175 psi), and a bottom panel is needed for vehicle traffic. The soil above the unit determines the maximum load.
Should I stack Flo-Wells or connect them side by side?
Both add storage. NDS recommends no more than 4 stacked and says connecting units in series is preferred over stacking. Stacked units need a bottom panel in the lower chamber.
What comes in the box?
Three interlocking side panels and one cover. Filter fabric, a bottom panel and a 6 in. surface inlet are separate NDS accessories.
More specs and the installation manual: NDS resource center.