Advanced Drainage Systems, the Hilliard, Ohio, maker of corrugated plastic drainage pipe, has agreed to buy StormTrap for about $530 million. The target designs underground precast concrete stormwater vaults and, by the trade press’s account, licenses their production to 11 independent precast manufacturers.
ADS announced the deal on Oct. 5 in a release filed with the SEC. The accompanying Form 8-K says the purchase agreement was signed Oct. 1. Net of the present value of expected tax benefits, ADS puts the price at roughly $450 million. StormTrap brought in about $165 million of revenue and about $40 million of adjusted EBITDA in the 12 months that ended in July. ADS will pay with cash and its existing credit facility, and it expects to close in the fourth quarter, pending antitrust clearance.
What the StormTrap acquisition buys
StormTrap is based in Romeoville, Illinois. Its SingleTrap, DoubleTrap and ShallowTrap systems are modular concrete chambers for detention, retention and infiltration under parking lots and buildings, and the catalog also covers treatment and trash-capture devices. ADS describes the sales process as spec-driven, which in practice means the product gets written into the civil drawings before a site contractor ever prices the job.
Concrete Products lists 11 licensed producers, among them A.C. Miller Concrete Products, Faddis Concrete Products and Wieser Concrete Products. The seller is PSP Capital, which bought StormTrap from Warren Equity Partners.
Do the division and the margin is about 24%. That’s a number that fits a company selling engineering and a license while somebody else owns the forms and the curing yard.
A plastic pipe maker moves into precast concrete stormwater storage
ADS already sells plastic stormwater chambers under its StormTech brand. On a tight urban site with heavy loads or shallow cover, engineers often go to concrete instead. After this deal, both answers come from the same parent.
That matters to anyone bidding underground detention. Plastic chambers and precast vaults have competed against each other on plenty of site packages, and one of the better-known independent names on the concrete side is about to belong to a company the trade press calls the leader in corrugated plastic pipe. Whether that changes pricing isn’t something the release addresses. It also doesn’t say what happens to the license terms those 11 precasters work under.
They didn’t sell anything. They just got a new licensor.
The ADS acquisition math: two deals, both at 10 times
ADS says the price works out to about 10 times trailing adjusted EBITDA, a multiple that counts expected run-rate cost synergies it doesn’t quantify. Strip the synergies out and the arithmetic is simple: $450 million over $40 million is a little more than 11 times, and the gross price is about 13.
The company used the same framing 12 months ago. In September 2025 it agreed to pay about $1.0 billion for NDS, the water management business of Norma Group, also at roughly 10 times with synergies included. That’s about $1.5 billion committed to stormwater products in just over a year.
At least the numbers are on the table. Cardinal Infrastructure put $120 million on its Allied Paving purchase, while Construction Partners bought two Abilene asphalt plants this week and disclosed nothing. ADS is closer to the first camp, with one gap.
The synergy figure is the gap. Until ADS states it, the real multiple sits somewhere between 10 and 13, and the precasters pouring the product are left to guess which costs the buyer plans to take out.