Hans soon found a partner in Ton van Beek. About 2 years after its establishment, Martien Meijer, an old student of Hans, joined the company. Martien has been a member of the board of directors since 1995, and since 2014 carries out this role together with Wouter Lengkeek and Eelco Waardenburg. In the early 1990s, sister company Deltamilieu, an employment agency for ecologists, was founded. Later, BWZ engineers, which has now become its own independent company, and BESE-products were founded.

Zeeland in the Netherlands has remained an important research area for Waardenburg Ecology. 'Het Zijpe' in Bruinisse has been owned by the company since the 1980s. Originally a waiting room and café for the local ferry, it was converted into a base for fieldwork in the delta and surrounding area. Since 1995, Waardenburg Ecology's main offices have been located in an historic mansion in the picturesque town of Culemborg in the centre of the country. A further location was opened in Nijmegen in 2020. As of 2022, we are now comprised of over 140 employees.

The Dutch company Koeman en Bijkerk bv was founded in 1994 through the merging of Tripos and Aquatic Ecosystems. Koeman en Bijkerk was the first commercial ecological consultancy with a quality assurance system based on ISO 9001 and later NEN EN 17025:2005. The company was led by Ronald Bijkerk and Karin Fockens. In 2017, it became part of Waardenburg Ecology under the name 'location Haren (Gn)' and has since grown from 13 employees to over 20 in 2022.