Say you manage a small municipal water system. A consultant mentions “C652” in a meeting, and everyone nods, though half the room isn’t sure what it covers. You’ve got a reservoir that’s due for a look and a nagging feeling that the paperwork might matter as much as the inspection itself. It often does.

This article explains what AWWA cleaning and inspection involves, based on Ven-Tech Subsea’s AWWA C652 page. It covers what the standard is, what changed in the 2025 edition and what it doesn’t tell you, so you can plan with fewer surprises.

A Disinfection Standard First

The page makes a point that surprises many people. AWWA C652 is a disinfection standard. It includes sanitary procedures relevant to underwater inspection and cleaning of potable water storage, but it doesn’t describe the technical aspects of the inspection or cleaning.

So the standard protects water quality, while the inspection method has to be defined separately. Ven-Tech develops the inspection route, cleaning scope and deliverables around the owner’s decision requirements. Both halves matter: sanitary control on one side, useful evidence on the other.

What the 2025 Edition Changed

Planning and Documentation

The page says the 2025 edition adds a requirement for a disinfection plan and, when warranted, a dechlorination plan. It also strengthens planning and documentation while keeping a practical route for minimally intrusive ROV or diver inspections when rigorous sanitary procedures are followed.

Chemicals and Terminology

The edition also adds chemical handling precautions, clarifies terms like free chlorine, total chlorine residual, contact time and highly chlorinated water, provides more disinfection method guidance and updates the response to initial positive coliform results. The complete standard should be reviewed for contractual use.

Where AWWA Cleaning and Inspection Fits

For many utilities, AWWA cleaning and inspection is the practical bridge between a regulatory expectation and a real tank. The reservoir needs to be inspected and cleaned, and the work itself must not contaminate the stored water. That’s the balancing act the standard addresses.

Ven-Tech uses potable grade commercial divers, ROVs and robotic cleaning systems, and says work may be completed with the reservoir full or isolated without draining where the asset, water quality objectives and owner requirements permit. Each recommendation, the page says, is based on the facility and not on a one method pitch.

Sampling and Water Quality

Planning may address coliform sampling, chlorine residual and aesthetic water quality considerations. The owner, operating authority and a qualified laboratory remain central to defining sampling locations, timing, acceptance criteria and return to service decisions.

That division of responsibility is worth noticing. The contractor documents equipment preparation, observations and agreed monitoring, but the decision to put the reservoir back in service stays with the owner. A good scope says so plainly, so nobody assumes the diver or the robot is signing off on water quality.

Chemical Handling and Discharge

The page mentions chemical handling controls and discharge awareness. Where chlorinated water must be discharged, the project team evaluates containment, dechlorination and environmental requirements, coordinated with the owner and applicable rules, rather than assumed from a generic template.

It’s an area that gets overlooked in early planning. Ask where the water goes, who approves it and what the plan is if levels are higher than expected. A few minutes spent on discharge during scoping can prevent a very awkward conversation later.

Choosing the Method

AWWA C652 services can be delivered by commercial divers, ROVs, robotic systems or a combined approach. Access dimensions, tank geometry, water use, visibility, sediment depth, required dexterity and operating constraints decide which is best. Divers suit touch and close access. ROVs suit remote inspection and cleaning.

A combined program uses robotics to establish condition first, then deploys divers only where direct inspection, cleaning or intervention adds value. Ven-Tech notes that hybrid planning can reduce unnecessary exposure while preserving the hands on capability needed for complex findings.

Getting Ready

Send the reservoir location, construction material, dimensions or capacity, hatch and access details, operating status, drawings, previous reports, estimated sediment, known concerns, schedule, deliverables and any owner specific disinfection or sampling requirements. Ven-Tech will review the method with you.

Reach the team on 604 230 3022 or info@ven-techsubsea.ca. For utilities that also want to understand the cleaning side, ask about water reservoir cleaning and inspection programs that cover more than one tank.

Conclusion

AWWA C652 protects the water, but it doesn’t tell you how to inspect the tank. That’s the part you plan around your own asset. With a disinfection plan, clear sampling responsibilities and a method matched to the reservoir, AWWA cleaning and inspection becomes a controlled, documented job instead of a worry.

FAQs

Is AWWA C652 an inspection standard?

No. It’s a disinfection standard with procedures relevant to underwater inspection and cleaning. The technical inspection is defined separately.

What did the 2025 edition add?

A disinfection plan requirement, a dechlorination plan when warranted, chemical handling precautions and clarified terminology.

Can a reservoir stay full?

Potentially, if the facility, water quality objectives, sanitary controls and authority requirements support it.

Who decides return to service?

The owner and operating authority, using sampling and laboratory results.