You could do a college course, which would teach you some of the skills and knowledge you need in this job. Relevant subjects include the Level 2 or 3 Diploma in Water Engineering.
You'll usually need:
- 2 or more GCSEs at grades 9 to 3 (A* to D) for a level 2 course
- 4 or 5 GCSEs at grades 9 to 4 (A* to C) for a level 3 course