| 1927 |
Emil O. Trojahn established Emil O. Trojahn Plumbing and Heating |
| 1958 |
Company relocates to 7922 Croydon Ave. St. Louis, MO |
| 1960 |
Name changed to Emil O. Trojahn & Son Plumbing Company, Inc. |
| 1969 |
Sidney A. Trojahn becomes third generation of Trojahn family to work at the business |
| 1971 |
Expanded offices at 7922 Croydon |
| 1977 |
Sidney A. Trojahn named President Sidney H. Trojahn named Chairmen of the Board |
| 1985 |
Sidney H. Trojahn retires |
| 1989 |
Design/Build capabilities added with addition of licensed engineer to staff |
| 1991 |
Name changed to Trojahn Plumbing Co. |
| 1997 |
Mark Trojahn becomes fourth generation of Trojahn family in the business |
| 1997 |
AutoCad capabilities added to engineering department |
| 2006 |
Company relocates to new 17,000 square foot complex at 1601 Sublette Ave. St. Louis, MO |
| 2006 |
Introduces Trojahn Plumbing Systems as new Corporate Identity |