ADS ANNOUNCES DOMESTIC AND INTERNATIONAL EXPANSION PLANS

HILLIARD, OH, January 14, 2005 — Advanced Drainage Systems Inc. (ADS), the world’s largest manufacturer of corrugated high-density polyethylene (HDPE) pipe, has announced plans to open four new manufacturing facilities located in the United States, Puerto Rico and Mexico. All plants will be operational within the next six to nine months. ADS currently operates 21 domestic and five international plants, along with 28 distribution centers in the United States.

Since first introducing corrugated HDPE pipe in 1966, ADS has led the industry in production and product development servicing the stormwater management industry. With growing approvals and acceptance, these announced plant expansions follow a long line of strategic growth.

“In the last 15 years, we have experienced solid growth as the civil construction industry has
embraced the substantial features and benefits of our N-12® pipe and related fittings and structures,” said Joe Chlapaty, president and chief executive officer of ADS. “Our products have shown substantial benefits in both cost and performance compared to corrugated steel and reinforced concrete pipe.”

“Since 1995, we have built five domestic and five international facilities, and have substantially
expanded every one of our existing plants,” added Jim Baich, vice president, plant operations for ADS. “In every instance, we have supported market demand by building or expanding plants to accommodate the acceptance of our products.”

The two domestic facilities will both be located in the eastern half of the United States. “Through the efforts of our field sales and engineering personnel, we have successfully demonstrated the improved performance of N-12 pipe over reinforced concrete pipe throughout the northeast corridor,” said Bob Klein, vice president of customer relations. The result will be a 60,000 square foot plant located in the greater Philadelphia area servicing eastern Pennsylvania, New Jersey and the surrounding states producing pipe and Nyloplast® engineered drainage structures.

“Another growth area has been in the southeast section of the country where our N-12 pipe shows significant improvement in both corrosion and abrasion performance over corrugated steel pipe,” Klein added. This will result in the relocation of the company’s Montezuma, GA plant to a larger, more centrally located area in Georgia.

On the international front, ADS continues to expand its global presence throughout Mexico, Central and South America. Having begun operations in Mexico through its ADS-Mexicana joint venture, this organization will now build its third manufacturing facility to be located in the Mexico City vicinity. “We have established a strong reputation in Mexico after building the first plant here five years ago,” said Chlapaty. “Through the efforts of our local partner, ADS-Mexicana has created a strong demand for our N- 12 pipe throughout Mexico, and specifically in Mexico City. Today ADS pipe is the most widely specified HDPE pipe in Mexico,” Chlapaty added. “For nearly 10 years, we have continued to increase the demand for our pipe in the Caribbean,”

Chlapaty continued. “This made us decide to build a new facility in Puerto Rico to better serve this growing area. The new plant will strengthen our presence in Latin America and complement our other plants in Guatemala, Costa Rica and Chile.” The new plant will be operational in late 2005.

“These new plants confirm our commitment to offer the best customer service in the industry,”
Chlapaty emphasized. “There is no other pipe company in the world who can deliver the proven product line of pipe, fittings, structures, chambers and geotextiles through nearly 60 points of distribution. Combined with the strong support of our independent distributors around the world, no other company even comes close.”

About Advanced Drainage Systems
Advanced Drainage Systems, Inc., (ADS), founded in 1966, offers a complete line of pipe and
fittings for superior water management. The company produces pipe in 3-inch to 60-inch diameters, in addition to a complete line of fittings and other accessories including StormTech® stormwater chambers,

Nyloplast drainage structures and geotextiles through its relationship with SI Geosolutions, and Naue GmbH. ADS currently serves the drainage industry through a global network of 26 manufacturing plants, 28 distribution centers and nearly 4000 independent distributors worldwide. To learn more about ADS, log on to www.ads-pipe.com, or call 800-733-7473.