October 6, 2014

Mr. Sean Conley

Standards and Risk Management Division

Office of Ground Water and Drinking Water (MC 4607M)

US Environmental Protection Agency

1200 Pennsylvania Avenue, NW

Washington DC 20460

RE: Distribution System Storage Facility Inspection and Cleaning

PUBLIC COMMENT

Dear Mr. Conley:

This letter is in response to ongoing conversations with Mr. Bob Clement, EPA Region 8,

and the Notice of Public Comment respecting the above referenced matter. Based on my 

firm, Liquid Engineering Corporation’s (‘LEC’), experience and expertise in this arena, this 

is a compelling matter that we believe all stakeholders would agree has remained 

unaddressed for far too long. I will be providing representative photographic documentation

under separate cover.

Introduction

In our experience there are three driving elements of potable water tank inspections; they 

are: The interval between inspections (i.e. frequency), the scope (i.e. level of detail) of the 

inspection, and method (i.e. wet/dry) of inspection. This comment will attempt to provide 

hard quantifiable data, in such a manner that the uninitiated reader will be able to extract 

this information, to assist them in formulating a proactive set of possible solutions to this

very significant issue of public policy and public safety in the drinking water industry. 

Background

Liquid Engineering Corporation (“LEC”) has been exclusively involved in potable water 

storage reservoir (tank) inspection, cleaning and maintenance for 25 years. Specifics of that 

experience include:

1. LEC has conducted inspections of approximately 50,000 potable water tanks 

throughout the United States during that quarter century of business.

2. LEC’s Customer Data Base includes approximately 30,000 water utilities in all 50

states.

3. LEC’s Customer Data Base incorporates both detailed historical (going back a 

quarter of a century) and current information on an estimated 75% of the total 

potable water production capacity in the U.S.
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4. LEC is the largest provider in the country of these highly specialized services.

5. LEC is both a Licensed Engineering Firm and Licensed Marine Engineering & 

Construction company, with licensed professional engineers and project managers 

on staff.

6. LEC was a member of the AWWA Committee tasked with drafting the updated 

potable water tank disinfection standards (AWWA C652-02).

Based on that experience and national exposure, I will describe in broad terms LEC’s 

experience and observations in the area of potable water tank inspections and 

maintenance, as it exists in the U.S. today.

Findings, Observations & Experience

Representative examples of findings:

 Inside a potable water tank located in one of the largest urban areas in the US was 

discovered the remains of three decomposed human bodies. It was estimated the 

murder victims had been in the tank, undiscovered, for 1-3 years. Subsequent

investigation determined that local drug dealers, knowing that the tanks were seldom 

inspected or for that matter, even visited, used it as a risk-free place to hide their 

‘competitors’; on three separate occasions. 

 A Liquid Engineering potable water tank inspection and cleaning found a fully 

decomposed adult horse skeleton lying in the bottom of the tank. [Years earlier when 

the tank had been open-topped, the horse had apparently entered the tank (which 

was shouldered into a hillside) for water, and unable to get out, had drowned. The 

water utility subsequently installed a roof on the tank (some time prior to LEC’s

inspection) without seeing the skeleton—for the simple reason that the tank had 

never been inspected internally, prior to LEC’s inspection.]

 LEC inspected and cleaned a potable water tank that had been sealed since 1941 

and never again entered, until our inspection in 1994. During that inspection we 

found approximately 18 feet of debris and accumulated organic material. The tank 

was in danger of imminent collapse and was ultimately decommissioned, based on 

our inspection findings. 

 Liquid Engineering often inspects and cleans potable water tanks that contain as 

much as 6-25 feet of various materials, including accumulated sand, organic 

material and/or mixed debris—that in most cases the utility is unaware is present.
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 As recently as this past spring, LEC identified several tanks that were constructed 

in the 1940’s and have NEVER been opened for interior inspection. When we

queried the owner, they stated that “if they inspected the tanks, they would have no 

choice but to do something to resolve the problems”.

 LEC regularly inspects and cleans potable water tanks (on a routine and continuing

nationwide basis) that contain 1-3 feet of accumulated organic and non-organic 

debris and sediment.

 On very rare occasions, LEC inspects a tank that contains accumulated debris, with 

embedded resident biological colonies and their associated byproducts, on the floor 

of the tank. These colonies can be anywhere from a few inches to 12 inches deep.

 LEC frequently finds floating debris and organics (dead birds, insects, snakes, 

rodents, mammals, and most commonly, pump lubricants) to a depth of 6–12 inches 

floating on top of the water, or lying on the bottom of the tank in various stages of 

decomposition. In this past four-week period, LEC’s six field crews identified 

decomposing snakes, frogs, birds, and a 14 foot long 8 inch diameter tree root that 

had penetrated a joint in a concrete potable water tank.

 An LEC potable water tank inspection at a US Government facility identified dozens 

of 6-12 in. long fish swimming around inside two of their potable water tanks. The 

fish were surviving by eating the 2-3 feet of live snails living on the bottom of the two 

tanks. We removed the snails; and assume the government’s employees caught 

the fish upon LEC’s departure, enjoying a great fish fry.

 In the recent past, LEC inspected and cleaned two potable water storage tanks that 

had never been previously inspected since the day they were placed in service, in 

1938 and 1947 respectively. 

 On a nation-wide daily basis, a routine, typical, and expected finding is 1-3 inches 

of accumulated bottom sediment and debris. In fact this finding is so customary that 

LEC does not charge extra to clean ‘up to’ that amount of accumulated material in 

its standard contract language. Typically this debris is composed of sand, dirt, inert 

organic material, iron compounds and various precipitating and flocculating agents 

used in the water treatment process.

 So far in 2014, LEC has identified more than 100 potable water storage tanks that 

have not been opened (i.e., inspected) for over 10 years.
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Relevant Statistics

Some statistics gleaned from LEC’s two+ decades of potable water storage tank 

inspections:

• In LEC’s customer base, approximately 70% of potable water providers, nationally, 

inspect and clean their potable water storage tanks at least every 3-5 years, with 

approximately half of these inspecting their tanks a maximum of every three years.

This time interval is not only an industry-wide ‘standard/best practices’ but is 

reflected in the American Water Works Association (AWWA’s) Standard M42, which 

specifies normal interior tank inspections no less than every 3 years, unless there 

are unusual levels of sediment accumulation, in which case it is recommended 

annually.

• In addition, AWWA’s Standard D101-53 (R1986) calls for interior inspection of all 

“potable water storage tanks at intervals not more than every 5 years”. It is important 

to note that it is not more than every 5 years, implying that more frequently than 

every 5 years is the desired inspection interval.

• Of the remaining 30% of potable water providers, the time between inspections and 

cleaning can be anywhere from 7-20 years but is, with LEC’s customers, on average 

around every 7-10 years.

• In LEC’s experience, virtually all potable water utility operators in the country would 

ideally like to inspect and clean their water storage tanks no less frequently than 

every three (3) years. Over the past two decades, neither my staff nor I can recall a 

single operator or utility manager who would oppose such an inspection interval. 

For those utilities that do not meet that frequency standard, it always seems to be 

for one of two reasons: Either a lack of money (i.e. it’s not the city’s “squeaky 

wheel”), or it’s the utility’s inability to lose the use of their single water storage tank 

during a ‘dry’ (empty tank) inspection or cleaning, thus preventing adequate capacity 

for fire protection or drinking water. (By utilizing a properly qualified, trained and 

experienced potable water diving contractor, the latter reason is rendered moot). 

• Of those estimated 30% of potable water providers that do not inspect and clean 

their water storage tanks on a regular basis (defined here as every 3-5 years), the 

most common reason LEC has heard—literally thousands and thousands of times 

over the past quarter century—is: “The city council/mayor/Board told me that as 

long as nobody is getting sick or no one is making us do it, we don’t need to spend 

the money”. 

• One of the key reasons that the 70% of potable water providers who do undertake 

routine inspections (in addition to the obvious public health and safety issues) is that 

it allows them to identify and quantify a variety of needed maintenance 

discrepancies.
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These include paint failure and associated corrosion in steel tanks, cracking in 

concrete tanks, developing structural issues - up to and including possible structural 

failure, potential tank contamination issues, and long-term maintenance budgeting and 

planning.

General Comments

Various AWWA Standards (as described above) recommend all potable water storage 

tanks be inspected at least every three (3) years. In our quarter-century of experience 

nationally, fewer than 40% of potable water tank owners (private and public) follow this 3-

year standard, generally as a result of funding limitations. In LEC’s experience in some 

50,000 water tanks nationwide, 99% of significant health and maintenance problems can 

be identified within any given 3-year inspection window, thus allowing adequate time for 

correction/mitigation before public health or safely is placed at risk.

[As a sidebar comment, since our earlier conversations with Mr. Clement, we have polled a 

number of utility operators and managers who have been unsuccessful in getting the money 

for more frequent inspections and tank cleaning (typically done every 7-10 years with the 

group we polled).

To a man (all happened to be men) they opined that they would love to see a Federal 

regulation that would mandate frequent tank inspections and cleaning (every 3 years was 

proposed to them, without one person demurring), because it would provide ‘top cover’ (i.e. 

“protection”) for the operators from the board/manager/city council—who would be left with 

no choice but to comply with the regulation, because it would now be a “squeaky wheel”.] 

In the event a particular potable water storage tank is found to have significant physical 

condition or potential public-health issues, this requirement should mandate annual 

inspections and monitoring (in emergency situations) until the identified discrepancies are 

rectified. 

Continuing State Regulatory Challenges

One of the specific issues facing thousands of single-tank community water systems is the 

occasional state-mandated requirement that tanks must be drained in order to be inspected. 

The hardship for these single-tank or intrinsic system design-limited communities is that 

during the 5, 6 or even 7 days required to drain, clean, inspect, refill, disinfect and test a 

tank before it can be placed in service, it can leave many of these communities without 

adequate drinking water or fire protection. This also ignores the extremely high cost of 

dumping the hundreds of thousands, or even millions of gallons of finished (i.e. expensively 

treated) water, prior to the inspection. 

The fall-out from this regulation is that many utilities simply don’t inspect their tanks. 

Mandatory tank draining is an onerous and ill-advised regulation, which while undoubtedly 

created with the best of intentions, is neither supported by any scientific evidence nor 

current best practices.
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On the contrary, the AWWA, as well as other nationally recognized organizations have 

developed and implemented standards, policies, procedures and best practices to ensure 

that the public health and safety are protected when undertaking ‘wet’ potable water tank 

maintenance activities.

These mandatory draining regulations should be specifically limited to the most exigent 

circumstances, and should require a written notice from the state regulatory authority to the 

utility as why this is requirement has been mandated in this specific instance. In short, 

mandatory tank draining is a vexing, even impossible compliance issue for thousands of 

water utilities across the country. [This regulatory issue is well known by the respective state 

regulatory authorities, and as a result is often ignored by them—turning a blind eye and 

tacitly allowing ‘wet’ (i.e. diver inspections/cleaning)—in order to facilitate critically needed

tank inspections, cleaning or maintenance.]

In the course of litigating with two state regulatory authorities to allow ‘wet’ (i.e. diver) tank 

inspections, LEC has actually been told by state regulators that they would rather see tanks 

go uninspected, than allow properly certified, trained and experienced potable water 

commercial divers to inspect their state’s water tanks. Under rigorous questioning, not one 

person could offer a science-based reason for their position. The result of this attitude is 

that hundreds and hundreds of potable water storage tanks in this country go uninspected 

year after year, after year, after year—often for decades.

As to the issue of the level of inspection detail described at the beginning of this statement, 

there is one state that currently has a regulation in place that mandates an annual inspection

of every potable water tank located within that state. On its face, this would appear to be a 

very proactive approach to maintaining water quality and storage tank condition monitoring. 

Unfortunately this is not the case, for the simple reason that the state-mandated “inspection” 

criteria can be met by simply opening the hatch on the top of the tank and looking inside 

the dark, water-filled reservoir. They are referred to, tongue-in-cheek, as “hatch peek” 

inspections. 

Summary

Those well-run and properly administered potable water utilities (the 70% nationwide) in the 

United States today almost universally inspect their water storage tanks on a frequent 

basis—typically every three years.

Only the most poorly administered water utilities (estimated 30% nationwide)—for financial 

or other reasons—do not meet even a minimum 5-year inspection period.

This lack of even minimal inspections appears indefensible on its face, when one considers 

that every water utility in the country undertakes the disinfection expense and effort of daily 

monitoring of both its water production and storage (water tank) facilities; yet on the other 

hand nearly one-third of these same utilities refuse to inspect their water storage system at

least once every 3 years.
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And this is doubly troubling when one considers the fact that a water utility’s potable water 

storage tanks are the final step in the process before the water is distributed to the families 

who drink it, including children, the elderly and those who may have compromised immune 

systems.

A three-year potable water storage tank inspection mandate would meet current

recognized, science-based, published (AWWA and others) standards and best practices, 

improve water quality, and identify potential problems before they become serious 

problems, thus ensuring both the public’s health and safety. All of these benefits could be 

had at nominal cost to the utility, and can be accomplished either with the tank empty or 

filled with water, thus offering no disruption in service or loss of expensive water to the utility.

Hopefully this information will be useful to USEPA in developing a responsive and wellcrafted final regulation. I appreciate the opportunity to provide input on this most important 

matter. 

Sincerely,

LIQUID ENGINEERING CORPORATION

Wayne Dykstra

Wayne Dykstra

President

CC: File