Expect to pay about $13,000/year to maintain a 400,000-gallon tank and about $23,000 for a 2-million-gallon tank. Photo: James Didawick
In a small community like ours — population 4,000 — the water storage tank is one of the largest and most visible landmarks. We have two: 2-mgd and .43-mgd.
Most water systems take justifiable pride in maintaining treatment plants and pipelines, parts of the water system that, although critical, are largely out of site and out of mind to the general public. But how many communities are just as proud of their storage tanks?
Instead of viewing maintenance as a necessary evil, consider this: That asset preserves the quality of your community's water, stores water that puts out fires, and maintains pressure throughout the system for the benefit of homes, restaurants, and businesses. The tank should receive the same type of regular preventive maintenance as a personal vehicle. At the very least, the maintenance contract should require:An annual inspection of both the tank and tower to ensure the overall structure is sound and watertightAn interior washout and inspection every other year. Check access covers, visible interior piping, valves, and lighting for normal wear and tear; and overflow flapper valves for debris that could hinder flow.
Breaking it down further, the maintenance contract also should require the service provider to:Use high-pressure equipment with chemical injection, as needed, to completely drain and clean the tank to remove mud, silt, and other accumulations that could harm the tank or contents. Upon completion, thoroughly inspect and disinfect the interior with a granular calcium hypochlorite mix in proportion to tank volume before returning the tank to service.Clean and repaint the interior and/or exterior when complete repainting, rather than touch-ups, is necessary.Determine the need for interior painting by the thickness of the liner and its protective coating, which the contractor should have examined during the interior washout.Determine the need for exterior painting by the protective condition and appearance of existing paint. Both the owner and contractor should look for peeling, blistering, or cracking; the side that faces prevailing weather conditions may be faded.When painting's necessary, use products and processes that meet or exceed local health department requirements; and check with the Steel Structures Painting Council for disinfection, surface preparation, and coating materials.Include logos and any other artwork in the checklist for exterior maintenance.Include a sample insurance certificate with the initial proposal.Follow state specifications for cleaning and coating potable water tanks. In our case, the Virginia Department of Health Office of Drinking Water Programs dictates operations and maintenance and preparation.Furnish relief valves if your system operates off a single tank or if one of a multiple of tanks is taken out of service for maintenance.Provide a written report detailing work done — whether an inspection, maintenance, or repair — that includes photographs, structure condition, types of services and repairs that were performed, and date and time. This document becomes an important part of the tank's history, and it gives new employees a thorough written record of operations and maintenance to which they can refer as they prepare to operate the tank.
Given our litigious society, it never hurts to have the proper documentation if you're ever faced with defending operational decisions.SAFETY AND SECURITY
In this post-9/11 era, it's also important to guard against the potential for vandalism and acts of sabotage.
One of the easiest ways to do this is to install a perimeter fence around the tank and an anti-climb device on all access ladders to prevent unauthorized persons from entering the tank area and climbing the tower. Title 29 in the Code of Federal Regulations provides requirements for the installation of anti-climb and fall-prevention devices.
Depending upon the size and height of your structure, a good anti-climb/fall-prevention device can be installed for a few thousand dollars.
Key control is another important factor in limiting access. Store spare keys to all locks on the tanks away from the tank — the treatment plant, municipal office, or police department office — so only authorized employees have access.
Whenever possible, ask local law enforcement to place tank sites on routine patrol routes.
Cell phone companies may want to install an antenna on the tank for better transmission and signal reception. Your maintenance contractor should be able to broker the space on your behalf and negotiate proper compensation. Approach tank maintenance like you would any investment that you expect to appreciate in value over time. Through thoughtful planning, that asset will provide many years of good service.
— Didawick (firstname.lastname@example.org) is the superintendent of public works for the Town of Woodstock, Va.