Who Can Take API 653? Eligibility and Tank Experience Explained
API 653 eligibility: how education and aboveground storage tank experience combine, what counts as experience, and why vessel or piping work does not.
Written by Nilanjan SenReviewed by Deepak Rawtal
Published 20 Oct 2026Reviewed 16 Oct 20263 min read
API 653 has no shortcut route. No other certification qualifies you to sit it, and the application is judged on two things: your education and your documented experience with aboveground storage tanks. This post sets out the requirements as API publishes them (checked against API's own pages on 16 October 2026), and the points that most often trip up an application.
Short answer: with an engineering or technology degree you need 1 year of tank inspection experience. With a 2-year diploma you need 2 years, with a high school diploma 3 years, and with no formal education 5 years or more. The experience must be from the last 10 years, with an authorised inspection agency, and it must be with storage tanks.
The requirements
API sets these out in Annex D of the API 653 standard.
| Your education | Experience needed | What the experience must cover |
|---|---|---|
| Bachelor's degree or higher in engineering or technology, or 3+ years of technical military service | 1 year | Supervising or performing inspection activities as described in API 653 |
| 2-year degree or certificate in engineering or technology, or 2 years of technical military service | 2 years | Design, construction, repair, operation or inspection of aboveground storage tanks, of which 1 year in supervising or performing inspection |
| High school diploma or equivalent | 3 years | As above |
| No formal education | 5 years or more | As above |
Two conditions apply to every row. The experience must be from the last 10 years, and gained while employed by, or under contract with, an authorised inspection agency. API verifies the experience you document on the application. Military service does not count after a dishonourable discharge.
Only tank experience counts
API treats API 510, 570 and 653 as three separate certifications, not three levels of one. Years spent inspecting pressure vessels or piping do not count towards an API 653 application. If your work has been mixed, document the tank part of it clearly: which tanks, what you did, and when.
Work that typically sits inside "design, construction, repair, operation or inspection" of tanks includes shell and bottom thickness surveys, internal and external inspections, settlement surveys, repair and alteration work, and hydrotest and reconstruction work. Describe what you did in your own words, but make the link to tanks obvious.
Four mistakes that delay an application
- Counting old experience. Anything older than 10 years does not count.
- Mixing equipment types. Vessel and piping years are not tank years.
- Vague descriptions. "Inspection engineer, 2019 to 2022" tells the reviewer nothing about tanks.
- Missing the deadline. Applications close about two months before each exam window. See API 653 exam fees and dates.
What API 653 leads to
Holding API 653 does not automatically qualify you for another API exam. Many tank inspectors go on to API 571, the damage mechanisms certification, and API 577 accepts a current API 653 as its qualifying route. For how the three equipment certifications compare, read API 510 vs API 570 vs API 653.
Keeping it after you pass
The certificate is valid for 3 years. To renew, API asks for three things:
- Work: at least 20% of your time over the last three years spent performing or supervising aboveground storage tank inspection. If you have not been doing that work, you sit the full exam again.
- Continuing professional development: 24 CPD hours in each 3-year cycle.
- A web quiz every 6 years: 25 open-book questions, with four hours to complete it.
You can apply up to 90 days before expiry, with a 90-day grace period after it. Late fees apply after the expiry date.
Next step
Once your experience lines up, plan your preparation; our API 653 study plan covers it week by week. Exam details and sample questions are in our API 653 certification guide.
