API 653 Tank Inspection Support in California

Short answer: In California, an API 653 tank inspection programme covers monthly owner checks, formal external inspections by an API 653 Authorized Inspector at least every five years, shell UT surveys on corrosion-based intervals, and out-of-service floor inspections. On top of that, the state adds its own rules: APSA through local CUPAs, CalGEM rules for oilfield tanks, and air-district limits on tank degassing. The owner's Authorized Inspector signs the report. Atlantis performs the NDE: floor MFL with UT prove-up, shell UT, weld examination and settlement data.

California's storage tanks sit in a setting no Gulf Coast state shares: high seismic hazard, some of the strictest air-quality rules in the country, a refining sector that has been closing and converting plants to renewable fuels, and oilfield tank farms in the San Joaquin Valley under their own state regulator. All of that affects when a tank can come out of service, what the inspection has to show, and who has to see the paperwork. This page explains where California's API 653 tanks are, what the code requires, which NDE methods produce the data, and how state and federal rules layer on top. Atlantis performs the NDE; your API 653 Authorized Inspector remains inspector of record and signs the inspection report. To start, send us your California tank list.

Where API 653 tanks are in California

Direct answer: California's field-erected tankage is concentrated in four regions: the Los Angeles Basin refineries and the marine terminals at the Ports of Los Angeles and Long Beach; the San Francisco Bay Area refinery and terminal belt from Richmond to Martinez and Benicia; the Kern County oilfields and Bakersfield area; and fuel terminals along the products-pipeline network serving San Diego, the Central Valley, Sacramento and the Inland Empire.

Los Angeles Basin, El Segundo, Carson, Wilmington and Torrance

Southern California's refineries in El Segundo, Carson, Wilmington and Torrance hold large crude, intermediate and product tank farms, and the marine terminals around the Ports of Los Angeles and Long Beach receive crude and products by ship. Many of these tanks are decades old, have been modified repeatedly, and sit within dense urban neighbourhoods, which raises the stakes of any release and keeps regulators and the public closely engaged. External floating-roof tanks dominate gasoline and crude service; air rules make roof seal condition a recurring inspection item.

San Francisco Bay Area: Richmond, Martinez, Benicia and Rodeo

The Bay Area refining belt runs along the Carquinez Strait and San Pablo Bay. Several plants have changed sharply in recent years: the Rodeo and Martinez refineries were converted to renewable diesel production, and others have announced reductions or closures. Conversion and closure change tank service from crude and gasoline to renewable feedstocks, vegetable oils and renewable diesel, or to idle and repurposed storage. A service change is exactly when the Authorized Inspector needs good baseline thickness and floor data, because corrosion behaviour, product temperature and the applicable inspection history all change.

Kern County and the San Joaquin Valley

Around Bakersfield, the large heavy-oil fields of Kern County operate thousands of production, wash, stock and produced-water tanks, many of them in heated or steam-flood service. These production tanks fall under the California Geologic Energy Management Division (CalGEM) rather than the CUPA tank programme, and CalGEM sets its own inspection and wall-thickness testing schedule. The area also has a small refinery and crude pipeline origin stations.

San Diego, Central Valley, Sacramento and the Inland Empire

Refined products move by pipeline from the refining centres to distribution terminals in Mission Valley, Colton, Fresno, Stockton, Sacramento and elsewhere, and military fuel depots support naval and air bases in San Diego and along the coast. These terminals have smaller tanks but large numbers of them, often with lean site staff, and they benefit from external inspection campaigns that cover several sites per mobilisation.

What API 653 requires, in plain terms

Direct answer: API 653, now the Fifth Edition with addenda through Addendum 4 (July 2025), sets the in-service inspection, repair, alteration and reconstruction rules for welded or riveted atmospheric steel tanks built to API 650 or API 12C. It requires routine monthly checks, formal external inspections, corrosion-based shell thickness surveys and internal floor-focused inspections, with intervals set from measured corrosion rates within code ceilings.

Routine in-service inspections are visual walk-downs by owner personnel, at intervals suited to the site but no longer than one month. They catch leaks, shell distortion, settlement, roof and seal damage, and coating and foundation deterioration.

External inspections are formal inspections by the Authorized Inspector. The maximum interval is five years, shortened to a quarter of the remaining shell corrosion life where that is less.

Shell ultrasonic thickness is measured at least every five years while the corrosion rate is unknown; once known, the interval is based on half the remaining shell corrosion life, with a fifteen-year maximum.

Internal inspections focus on the bottom and the shell-to-bottom region. The initial interval is ten years unless the owner takes credit for safeguards (linings, cathodic protection, leak detection, release prevention barriers), which can extend it to twenty years without a release prevention barrier or thirty years with one. Subsequent intervals follow measured floor corrosion rates and the minimum bottom thickness the code requires at the next inspection, within the same ceilings, or a risk-based programme that satisfies the code. The settlement annex guides evaluation of foundation movement.

These are the code's rules, and the interval decisions belong to the owner and the AI, not to Atlantis. For a worked explanation, see API 653 tank inspection intervals explained, and always confirm against the current edition available from api.org.

NDE methods for API 653 work in California

Direct answer: California tank NDE centres on floor MFL scanning with UT prove-up, shell and critical-zone UT, area corrosion mapping, visual examination including seal and roof condition, surface methods and vacuum-box testing after repairs, volumetric examination of new welds, and settlement data. Seismic damage and service changes after refinery conversions add their own scopes.

Radiography is performed only by crews licensed for industrial radiography in California. Procedures are reviewed by an ASNT NDT Level III, and technicians are certified to an SNT-TC-1A written practice. More detail: aboveground storage tank inspection and API 653 tank inspection support.

How Atlantis supports your Authorized Inspector

Direct answer: Atlantis takes the examinations your Authorized Inspector specifies, performs them, quality-checks the results and delivers a structured digital report. The AI evaluates, decides repairs and intervals, and signs. We are not an Authorized Inspection Agency and we do not supply API-certified inspectors; we supply independent NDE data.

California owners face a heavy documentation burden: APSA inspections by the CUPA, air-district records, CalGEM reports for oilfield tanks, and Cal/OSHA process safety records at refineries. Clean, traceable NDE data reduces friction across all of them. The handoff:

1. Scope from the AI's plan, including coverage, report format and any regulator-specific data the owner needs.
2. Level III procedure review for the tank's materials, coatings and condition.
3. Examinations: floor scanning and prove-up, shell and critical-zone UT, weld examinations and settlement readings.
4. Data QA against calibration records and prior surveys before demobilisation.
5. Digital report in our reporting platform: floor maps, shell readings by course, weld records, photographs, calibration data and technician certifications.
6. AI evaluation and sign-off, including repair decisions and next intervals.
7. Reuse at the next interval, with optional digital twin visualisation or inspection-management ERP tracking.

We can calculate corrosion rates and remaining life from our data for the AI's review; the interval remains the AI's and the owner's decision. Atlantis performs the NDE; your API 653 Authorized Inspector remains inspector of record and signs the inspection report. Request an NDE scope for your AI's plan.

California regulations that sit on top of API 653

Direct answer: California layers several regimes over API 653: the Aboveground Petroleum Storage Act administered by CUPAs under CAL FIRE's Office of the State Fire Marshal, CalGEM production-facility rules for oilfield tanks, air-district rules on tank seals and degassing, Cal/OSHA refinery process safety, and federal SPCC and PHMSA requirements. Confirm current requirements with each agency.

Aboveground Petroleum Storage Act (APSA)

APSA (Health and Safety Code, Chapter 6.67) applies to tank facilities storing 1,320 gallons or more of petroleum in aboveground containers of 55 gallons or more, among other triggers. It requires those facilities to prepare and implement an SPCC plan meeting the federal rule, and it is enforced locally by Certified Unified Program Agencies (CUPAs) with CAL FIRE's Office of the State Fire Marshal providing state oversight. In practice, the CUPA inspector will look for evidence that tank integrity testing follows the standard named in the plan, typically API 653 for field-erected tanks.

Federal SPCC (40 CFR Part 112)

The SPCC rule requires bulk storage containers to be tested or inspected for integrity on a regular schedule and whenever material repairs are made, according to industry standards: API 653 for field-erected tanks and STI SP001 for shop-built tanks are the usual choices. APSA makes this a state-enforced obligation as well.

CalGEM production facility rules

Tanks between the wellhead and the sales meter fall under CalGEM's production facility regulations (Title 14, California Code of Regulations, starting at section 1773). These require monthly operator inspections of in-service tanks, periodic wall-thickness testing (at least every five years where the corrosion rate is unknown, with longer intervals allowed on approved calculations), and periodic inspection of bottom plates. UT thickness surveys and floor scanning are the NDE behind those obligations. Confirm current requirements with your CalGEM district office.

Air districts: seals, cleaning and degassing

Air districts regulate emissions from storage tanks. In the South Coast district, for example, rules cover floating-roof tank seals and the cleaning and degassing of storage tanks (Rule 1149), including notification before degassing. That directly affects internal inspections: a tank cannot simply be opened, and degassing must follow the district's control and notification requirements. Plan the NDE start date after the district-compliant degassing is complete. The Bay Area and other districts have their own equivalents; confirm with your district.

Cal/OSHA process safety and PHMSA

California refineries operate under Cal/OSHA's refinery process safety management standard (Title 8, section 5189.1), which goes beyond the federal PSM rule in areas such as damage-mechanism reviews and hierarchy-of-controls analysis; tanks within covered processes are part of mechanical integrity. Pipeline breakout tanks fall under 49 CFR 195.432, which requires API 653 inspection; the rule currently references the 2001 Third Edition and excludes the risk-based internal-interval option, and a June 2026 PHMSA proposal would update it to the Fifth Edition. The Office of the State Fire Marshal's pipeline safety division regulates intrastate hazardous-liquid pipelines in California. Marine oil terminals have their own engineering and maintenance standards (MOTEMS) under the State Lands Commission, covering wharf structures and piping rather than shore tankage.

Planning around seismic events, air rules and conversions

Direct answer: California tank NDE has to be timed around degassing permits and notifications, refinery turnarounds, refinery conversions and closures, and post-earthquake inspections. External inspections and shell UT can run in service all year; internal work starts only after compliant cleaning and degassing.

Seismic events. Earthquakes can damage storage tanks through shell buckling at the base (the classic "elephant's foot"), roof and seal damage from liquid sloshing, broken nozzles and piping connections, anchorage failure and foundation movement. Owners often run a rapid post-event visual survey, then targeted UT, MT or PT where damage is suspected, with settlement readings compared against the last survey. The AI uses those results to decide whether a formal inspection or repairs are needed before return to full service.

Degassing. Because degassing is controlled by air rules, the internal inspection window is set partly by the air permit and the degassing contractor. Agree the NDE coverage and crew start date before the tank is opened, so the floor scan starts the day entry is permitted.

Conversions and closures. When a tank moves to renewable feedstock, renewable diesel or a different product, the AI typically wants a complete baseline: shell thickness, floor condition and nozzle condition. Closures and idling call for documentation of condition at the point the tank leaves service, which saves time if it is ever reactivated.

To plan a campaign around your permits and outages, book a scoping call.

API 653 inspection support across California

Direct answer: Atlantis mobilises crews to tank sites anywhere in California, with dates agreed during scoping. The pages below describe local tank, corrosion, piping, pressure-vessel and third-party inspection work in the state's main industrial areas.

• Los Angeles Basin:corrosion inspection in Los Angeles, pipeline inspection in Los Angeles and third-party inspection in Los Angeles.
• San Diego:tank inspection in San Diego and corrosion inspection in San Diego.
• San Francisco Bay Area:corrosion inspection in San Francisco.
• Kern County:third-party inspection in Bakersfield.

For the piping and pressure equipment connected to tank farms, see our companion hubs for API 570 piping inspection in California and API 510 pressure vessel inspection in California, and the statewide NDT inspection services in California page. Pipeline operators can also see pipeline inspection services.

What to send us for a quote

Direct answer: Send the tank list, the last API 653 report, your AI's required examinations, cleaning and degassing status, and target dates. We will return a scoped NDE quote within 24 hours.

1. Tank list and drawings: tank numbers, diameter, height, roof and seal type, product (including any planned service change), plate thicknesses, annular ring, lining and anchorage details.
2. Last inspection report: previous external and internal reports, floor maps, shell readings, settlement surveys and any post-earthquake inspection records.
3. The AI's inspection plan: examinations required, coverage and report format, plus any CUPA or CalGEM documentation needs.
4. Access, cleaning and degassing: degassing schedule and air-district notification status, gas-free and confined-space arrangements, scaffold or rope access.
5. Dates and constraints: outage windows, refinery safety orientation, port access credentials, and whether the tank is a PHMSA breakout tank.

Get a quote within 24 hours.

Frequently asked questions: API 653 tank inspection in California

Who can perform an API 653 inspection in California?

An API 653 Authorized Inspector, employed by the owner or an inspection agency, directs the inspection and signs the report. Qualified NDE contractors perform the examinations. Atlantis performs that NDE with ASNT-certified technicians under Level III oversight and hands the data to your AI.

Does California require API 653 inspections?

Not by a single statute, but in practice most field-erected petroleum tanks end up there: APSA requires an SPCC plan, SPCC requires integrity testing to an industry standard, PHMSA requires API 653 for breakout tanks, and Cal/OSHA refinery PSM expects recognised practice. Oilfield tanks follow CalGEM rules. Confirm with your CUPA and regulators.

Who enforces APSA?

Certified Unified Program Agencies (CUPAs), usually county environmental health or city fire departments, under oversight from CAL FIRE's Office of the State Fire Marshal. Facilities with 1,320 gallons or more of aboveground petroleum storage are typically in scope.

How often must a tank be inspected under API 653?

Monthly owner checks; a formal external inspection at least every five years or sooner with fast shell corrosion; shell UT on a corrosion-based interval; and internal inspections set from floor corrosion rates within code ceilings of twenty or thirty years, unless a qualifying risk-based programme applies.

What inspections follow an earthquake?

Owners usually run a rapid visual survey for base buckling, roof and seal damage, nozzle and piping damage, anchorage and foundation movement, then targeted UT, MT or PT and settlement readings where damage is suspected. The AI decides on further inspection or repairs.

Can you inspect while the tank stays in service?

Yes for external visual examination, shell UT, accessible-area corrosion mapping and settlement readings. Floor scanning and internal weld work need the tank emptied, cleaned and degassed in line with air-district rules.

Is Atlantis an Authorized Inspector?

No. We are not an Authorized Inspection Agency and we do not supply API-certified inspectors. We perform and interpret the NDE; your Authorized Inspector evaluates it, sets intervals and signs as inspector of record.

What certifications do your technicians hold?

Technicians are certified to an ASNT SNT-TC-1A written practice in each method, under ASNT NDT Level III procedure review. Radiography is carried out only by crews licensed for industrial radiography in California.

What will the report contain?

Floor maps with indications and UT prove-up values, shell readings by course and location, critical-zone readings, weld records, settlement data, photographs, procedures, calibration records and technician certifications, delivered digitally.

Do you perform RBI or fitness-for-service assessments?

No. Those are carried out by the owner's engineers or specialist consultants, for example when evaluating seismic or settlement damage. Atlantis supplies the inspection data they rely on.

Do you offer API 653 certification training?

No. Atlantis provides ASNT SNT-TC-1A NDT training only, including NDT training in California. For the API certification route, see our API inspector career guide.

How soon can a crew reach Los Angeles, the Bay Area or Bakersfield?

Crews are mobilised to your site on a schedule agreed during scoping, timed around your degassing and outage window. Send your tank details for a quote within 24 hours.

Plan your California tank inspections

Whether you are preparing for a CUPA inspection, a refinery conversion or a terminal outage, start with your AI's plan and your tank list. Send us your tank list, or see NDT consulting in California for Level III procedure support.

More Atlantis NDT services in California

• NDT training and certification in California
• Level III consulting in California
• NDT inspection services in California
• API 510 pressure vessel inspection support in California
• API 570 piping inspection support in California
• NDT ERP software in California
• Practical NDT simulator in California

Part of the wider aboveground storage tank inspection service at Atlantis NDT.