Externship Program
Every year, we host a free, virtual/in-person program for students and recent grads to learn about careers at Central San and in wastewater!


At Central San, we take pride in our work. To share careers in wastewater with students and recent graduates, we host an annual Externship Program for students and recent graduates from schools all over the country. Our cohort-style learning experience is designed as an insider look at multiple career paths in the wastewater industry and an opportunity to make connections, not only with established staff at Central San but also with fellow externs. The program is free, convenient (virtual with an optional in-person day), and customizable; it can include a range of Central San’s careers as well as any specific careers or departments the externs might be interested in. 

This year, we are excited to begin accepting high school students into our program!

When we launched the program in 2021, we welcomed 45 externs from colleges all over the country. Here are some of the comments they shared with us on their experience:

  • What inspired me was seeing how well maintained the grounds are and how happy everybody seemed. Also the fact that there is hardly any turnover and there is so much opportunity for growth. I love all of things central san does for the environment and the community and it all inspired me to not give up and to keep trying to go after my goal to work at a water treatment facility.
  • I came to this program motivated to enter the water sector, and I appreciate the opportunity to have more conversations with professionals in the field. Starting my study during the pandemic has left me very aware of the gap between my dining room table and an active plant processing millions of gallons every day, and I feel the most important thing for my own development and to engage and support potential workers is face time, shadowing, and applied experiences. I’m grateful that Contra Costa has allowed any student to have an inside look at a thriving and forward-thinking community of professionals.
  • The program is a really great way to develop an understanding of the wastewater treatment industry from the service provider perspective. There certainly was a lot of information presented that is not communicated in academic coursework.
  • Thank you for the great experience. The externship has inspired me to enroll into the Ken Kerri wastewater course through Sac State. I’m excited to take these courses and begin my journey into the wastewater industry. 


If you are interested in joining our next Externship Program, please fill out this interest form. You will be emailed when we announce our next session.


  • An extern must be currently enrolled in an accredited school, college, university, vocational or technical school. All academic standings and majors are welcome. Students who are not currently enrolled may also qualify to be an extern if they have graduated from college within the last year. Interested high school students may also apply.
  • Externs are considered “at-will,” short-term, non-continuous visitors with no grievance rights, benefits, or guarantees of regular employment with the District.
  • Students under the age of 18 may apply and attend with a signed permission slip from a parent or guardian. Please note in your application if you are under 18 so we may send you the form to be signed.


This externship is an unpaid position. Students are responsible for all expenses related to the externship, including travel, accommodations (if any), meals where not specified, etc. 


A career in wastewater is a rewarding and challenging path that not everyone may consider. We offer jobs for a range of majors and fields of study. Check us out and see if there might be a place you’ll fit in – whether at Central San or somewhere else in the wastewater community!


There will be four half-day virtual sessions (Monday through Thursday) where you’ll hear from wastewater professionals representing every division at Central San and be able to ask them questions. On the fifth day (Friday), there will be an optional in-person full day on site (lunch provided) at our Martinez, CA campus – filled with tours and activities to supplement what you’ve learned throughout the week. We highly encourage you to attend the Friday on-site day so you can meet fellow externs and see our staff in action.


Not sure if there’s a nexus between your field of study and what we’ll be covering in the program? Have any other questions? Don’t hesitate to contact externships@centralsan.org.