KLM’s Interpretation of the CDPHE Storage Tank Rule: Five Year Comprehensive Inspection
What should my inspection firm really be providing?
The Colorado Department of Public Health and Environment (CDPHE) Storage Tank Rule (STR),
effective on April 1, 2016, which requires a comprehensive tank inspection every five years and
has challenged municipal, rural water providers, and tank inspection companies with the
interpretation of a comprehensive tank inspection. The descriptor used by the CDPHE,
comprehensive, can be further explained as incorporating all components or details of the subject
tank; thus, giving greater clarity to CDPHE intentions.
Moreover, the heart of the Storage Tank Rule is to safeguard consumers from the tough effects of
minimal maintenance practices. Caused in part from neglect, inadequate asset management, or
lack of compliance with governing CDPHE guidelines, applicable AWWA, or OSHA standards.
The STR addresses this issue and establishes direction for asset owners and managers.
To help those owners and managers select a proper firm to perform these inspections, STR
Appendix A, recommends that any contracted firm provide a Statement of Qualifications (SOQ).
Listing experience, credentials, knowledge of applicable standards, certified inspectors through
the National Association of Corrosion Engineers (NACE), and degree of structural knowledge
needed address the multitude of tanks styles and possible deficiencies. These are essential skills
that owners and managers must consider when selecting a firm for inspection services.
A review of the STR, clearly indicates CDPHE’s primary concern focuses on five inspection
Inspecting a tank to provide a comprehensive evaluation requires extensive knowledge of all
tank classifications, fabrication, nomenclatures, construction practices, and applicable
standards¹ covering topics such as cast-in-place and post-tensioned concrete tanks, bolted tanks,
coated steel tanks, and an understanding of all entry points. Clearly document in the inspection
report the actual structural condition of the tank and compliance with current guidelines.
Evaluating a tank while in-service has become a common and efficient practice, allowing the
water to maintain its level of sanitation while performing an underwater remote operated
vehicle (ROV) inspection. A visual assessment of water quality should be recorded in any
inspection report. Some of the points to cover within the report are the water clarity, sediment
on the floor, use of a mixer, and evidence of biofilm, scum or refuse. Giving insight as to whether
the tank would pass a state-sanctioned sanitary survey and provide recommendations.
Security and Safety:
Tanks and elevated tanks are unmistakably potentially dangerous work sites. The firm
performing the inspection would not only implement OSHA requirements while inspecting but
should identify those items relating to the tank and providing such information in the report.
Those items may include climbing ladders, cages, fall prevention devices, confined space,
egress points, handrails, manway, and hatch requirements. Failure to perceive these items is
arguably the most serious repercussion of an unsuccessful inspection.
Coatings and Cathodic Protection System:
Steel tanks are painted and coated to prevent corrosion and degradation from exposure to the
elements. The role of any coating and cathodic protection system is to protect and defend
against those elements for as long as technologically possible. The believed function of the
five-year comprehensive inspection is to assess and lend a degree of asset management to these
structures and provide a rehabilitation timeline, and engineers cost estimate.
The CDPHE website provides examples of information and documentation that is suggested
to meet their intention of a complete comprehensive inspection. The assumed objective of the
STR by documenting and observing these assets is to provide owners and managers
information on their current tank conditions to make informed decisions. These inspection
reports are often the most reliable way to share tank information with councils or service
KLM Engineering, Inc.’s twenty-five years of experience in evaluating tanks of all types and sizes,
utilizing remote operated vehicles (ROV), float down, or dry tank cleanout inspections is precisely
the service the CDPHE is requiring. Having seen firsthand the high cost of tank neglect and poor
asset management, KLM works hard to ensure owners and managers are receiving complete
information with genuine recommendations. After the inspection has been completed, the written
report and photos are examined, and a final report is generated. Each report is reviewed and
stamped or signed off by a professional engineer and NACE inspector, adding a level of assurance
KLM advocates that each owner or manager should conduct research on inspection firms to
confirm they will provide the greatest assurance of STR compliance that establishes a superior
foundation of planned asset management and maintenance.
KLM Engineering, Inc. – Protecting Americas Water One Tank at a Time
¹Applicable standards include:
ACI 201 – Guide for Conducting a Visual Inspection of Concrete in Service
AWWA Manual 42 – Steel Water Storage Tanks
AWWA D100-11 – Welded Carbon Steel Tanks for Water Storage
AWWA D101-53 – Inspecting and Repairing Steel Water Tanks, Standpipes, Reservoirs,
and Elevated Tanks, for Water Storage
AWWA D102-11 – Coatings Steel Water Storage Tanks
AWWA D103-09 – Factory-Coated Bolted Carbon Steel Tanks for Water Storage
AWWA D104-11 – Automatically Controlled Impressed-Current Cathodic Protection
AWWA D107-10 – Composite Elevated Tank for Water Storage
AWWA D108-10 – Aluminum Dome Roofs for Water Storage Facilities
AWWA D110-04 – Wire and Strand Wound Circular, Prestressed Concrete Water Tanks
NFPA 22 – Standard for Water Tank for Private Fire Protection
NFPA 25 – Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems
OSHA 29 – Occupational Safety and Health Standards