The Lake of the Ozarks’
Sewage Woes
Problems and Needs
Benjamin Atkins
December, 2011
Fig. 1 - the Lake of the Ozarks
Source: http://mosportfishing.webs.com/apps/photos/photo?photoid=87296547
A Lake of Sewage?
Any resident of the state of Missouri should be aware of and perhaps familiar with the popular summer
destination that is the Lake of the Ozarks. Every weekend the lake attracts a steady stream of visitors for
a grand time of swimming, boating, shopping, and carousing. However, the lake and its community have
had to deal with troubles of late…
In 2007 the city of Lake Ozark’s municipal wastewater treatment facility discharged perhaps as many
as 15,000 gallons of untreated sewage directly into the Lake of the Ozarks [1]. Missouri
Department of Natural Resources (DNR) personnel observed this failure of the city’s septic system
and brought it to the attention of city officials, who promptly stopped the flow [1]. However, the city
did not provide DNR with any written report of the system failure and waited several days to begin
any cleanup efforts in the contaminated area of the lake [1]. In 2008 the city paid a $50,000 fine over
the incident [1].
In 2009 Missouri DNR inspectors found that of 419 wastewater treatment facilities discharging
treated effluent directly into the Lake of the Ozarks by DNR permit, 154 were in some violation of
DNR requirements [2].
Also in 2009, Missouri DNR was engulfed in controversy after its decision to delay by nearly a
month the release of test results that showed E. coli levels as high as 19 times the state standard in
some Lake of the Ozarks water samples [3].
All of the above incidents made news, and all should raise eyebrows among Missouri citizens who live or
spend their vacation time at the Lake of the Ozarks. Lovers of the Lake of the Ozarks need not panic:
Despite a number of DNR-collected water samples showing elevated E. coli levels, water quality across
the lake is generally quite safe for swimming [4], [5]. However, as the lake’s popularity continues to rise,
and as surrounding communities continue to grow and develop, water quality maintenance in the lake
should be an increasingly serious concern for the lake region’s many denizens.
This paper hopes to provide concerned citizens with a better understanding of the consequences of
ineffective sewage management that they might attach due importance to the maintenance of their own
septic systems, particularly those that are on-site. It also calls on those who enjoy the Lake of the Ozarks’
recreational attractions to become involved in the community effort to monitor and protect the lake’s
water quality.
Trouble in the Water
The total population of the many towns and communities that surround the Lake of the Ozarks is
comfortably above 80,000 and growing [5]. A significant portion of the region’s growth may be
attributed to retirees moving to the lake to enjoy their golden years, and many of these incoming residents
will be converting seasonal and weekend retreats into year-round homes [5]. As use of the lake grows
along with the population, the environment as well as the infrastructure of the surrounding communities
must bear the burden of the waste that concentrated population brings. If this burden becomes too great,
the immediate effects will be apparent in the lake region’s most important natural feature: its water.
The Missouri Department of Natural Resources, in partnership with other organizations such as the Lake
of the Ozarks Watershed Alliance, monitors water quality in the Lake of the Ozarks by analyzing water
samples for levels of E. coli [4].
E. coli is a form of bacteria, found in the intestines of both humans and animals, some strains of which
can cause severe illness usually characterized by diarrhea and abdominal cramps [6]. E. coli must be
provided with warm, damp surroundings in order to thrive, and so does not usually persist very long when
deposited in a harsh, open environment [7]. However, the bacteria can live for days or even weeks in, for
instance, a lake or stream [7]. The presence of certain strains of E. coli in lake-water represents a
significant health hazard in its own right, however most strains are harmless [6]. Nonetheless, E. coli
levels are used to provide a general indicator of water quality [6]. E. coli usually only ever finds its way
out of an intestine and into a water source via feces. Its presence in a lake or stream in large numbers
reveals that untreated sewage or some other source of fecal contamination has polluted the water [6].
Fecal contamination infuses an overabundance of nutrients into the water, disrupting the lake’s
ecosystem, and introduces a host of dangerous pathogens that can be picked up by unsuspecting
swimmers [8].
Missouri DNR states that it is its policy to close state beaches when E. coli levels exceed 235 colonies per
100 mL of water in a single sample or when the geometric mean of samples in an area exceeds 126
colonies per 100 mL [9]. Naturally, a moderate public hubbub arises when the organization finds highly
elevated levels of E. coli at public beaches. In June of 2009, Missouri DNR found water samples at one
Lake of the Ozarks beach which indicated E. coli levels might be as high as 2,419 colonies per 100 mL
(see Fig. 2) [9]. As recently as September of 2011, a study conducted by Missouri DNR in collaboration
with the U.S. Geological Survey and the Missouri University of Science and Technology found some
water samples with E. coli concentrations as high as 5,300 colonies per 100 mL [4].
3000
2500
2000
1500
2009 Data: E. coli single sample
maximums (mpm/100mL)
1000
State Standard
500
7-Sep
31-Aug
24-Aug
17-Aug
10-Aug
3-Aug
27-Jul
20-Jul
13-Jul
6-Jul
29-Jun
22-Jun
15-Jun
8-Jun
1-Jun
25-May
18-May
0
Fig. 2 – 2009 sample maximum E. coli levels at an unspecified Lake of the Ozarks beach over time
An alarming spike in mid-June is followed by a long period of desirably low E. coli levels.
Modified from Public Beach#1 chart at http://www.dnr.mo.gov/loz/bea chstudy.h tm (Source [9])
It must be noted that E. coli levels can fluctuate from location to location within the lake and even from
day to day [2]. For example, heavy rainfall washes surface waste, both human and animal, into the lake,
potentially resulting in elevated short-term E. coli levels [5], [7]. Many of DNR’s higher E. coli samples
were taken at times during which recent heavy rainfall was noted [4], [10]. As E. coli washes into the
lake and, normally, dies off at a reasonable rate, occasional concentration spikes are not necessarily panicworthy.
It must also be noted that most of the water samples collected by DNR and other organizations show
concentrations safely below the state standard [4], [9], [10]. Still, excessively high E. coli concentrations,
even if localized and even if short-lived, are a major concern for state and local officials, not to mention
the general public, if only because of the dire consequences involved in the un-looked-for event of an
outbreak of confirmed E. coli infections. While massive sewage discharges into the lake, such as that
perpetrated by the city of Lake Ozark on 2007, certainly do not help the effort to keep the lake clean, the
general consensus among lake observers is that the biggest threat to the lake’s water quality is in fact
thousands of small, aging, so-called ‘on-site’ septic systems each of which fulfill the wastewater
treatment needs of a single home [5].
On-site Systems
For the resident of a typical urban area, wastewater produced by his or her home is piped away to a large
municipal or regional facility in which the sewage from thousands of households is collected, filtered, and
treated before being released back out into the environment as clean water [11]. However, many houses
in the Lake of the Ozarks region are built in small, relatively secluded communities. Distance and terrain
combine to make it expensive or impractical for many area residents to connect their home to any existing
municipal or regional sewer system [5].
As a result, thousands of homes make use of individual ‘on-site’ sewage treatment systems. Such
systems generally consist simply of a septic tank and a soil absorption field, or leaching field.
A simple septic tank seals and stores sewage, allowing it to settle and separate into solid sludge, which
sinks to the bottom of the tank; liquid effluent; and floating scum, consisting of grease, oils, and lowdensity solids [12], [13]. Scum and sludge are simply stored in the tank until they accumulate to the point
that they must be pumped out and sent to a specialized treatment facility or otherwise disposed of [12],
[13]. Effluent is kept in the tank for some time then piped away to the leaching field [12], [13]. While in
the tank, naturally present bacteria and other microorganisms digest and decompose some of the nutrients
and pollutants in the wastewater [12], [13]. Ideally, sewage should sit in the tank for at least several days
before being dispersed into the soil [13]. Eventually, effluent passes through a filter to remove any
stubborn solid contaminants and is distributed through a system of pipes and trenches across the leaching
field, into which it is absorbed [12], [13]. As the effluent percolates down through the soil, contaminants
are further broken down and filtered, until the effluent is finally reduced to a reasonably clean state and
can mix safely with the groundwater (see Fig. 3) [12], [13].
On-site systems can be practical and effective, but they are subject to failure. The tank must be properly
installed and maintained. It should be air-tight and durable. Furthermore even a large, well-designed
septic tank must eventually be pumped free of sludge. If too much solid sludge accumulates in the
bottom of the tank, effluent will move through the system too quickly, or, in extreme cases, the system
may back up [12], [13]. Also, the success of the system is very dependent on the quality of the soil in the
leaching field. According to the Environmental Protection Agency’s (EPA) Onsite Wastewater
Treatment Systems Manual, only about a third of U.S. soil is suitable for on-site sewage filtration [12].
Little of the soil surrounding the Lake of the Ozarks falls into this third [5]. If soil is too dense, it will not
have the capacity to store and filter more than a minimal quantity of effluent. In this case, wastewater
may back up, polluting surface water [12], [13]. On the other hand, soil must be deep and even enough to
effectively absorb, filter, and purify effluent before it enters the groundwater [12], [13].
drain field
septic tank
soil absorption
soil layers
purification
groundwater
Fig. 3 – diagram of a basic on-site septic system
Source: http://www.epa.gov/owm/sep tic/pubs/septic_2002_osdm_all.pdf [12]
The EPA’s first published guidelines for safe and effective on-site treatment systems came in 1980 [12],
and the state of Missouri did not implement stringent installation standards for on-site systems until 1994
[5]. Many systems in the Lake of the Ozarks area were installed around or prior to these dates [5].
Consequently, many systems still in use today were installed carelessly in inappropriate soil and are not
likely to have benefitted from much maintenance over the years [5], [14]. Old, problematic systems are
often tolerated by Lake of the Ozarks owners because, if the owner does not use the residence full-time,
the system may not be called upon to handle an ordinarily large amount of sewage [5]. More importantly,
replacing an old system with a modern one can be quite expensive: up to $35,000 [15].
Unfortunately for environmental concerns, the responsibility for maintaining a working sewage treatment
system often rests almost entirely on the shoulders of the property owner. No state agency can even say
for sure exactly how many on-site systems are in place around the Lake of the Ozarks, though the number
is estimated to be between 15,000 and 20,000 [5]. When dysfunctional systems are detected or reported,
it can be difficult or impossible to compel an unwilling homeowner to pay for maintenance or
replacement [5], [15]. As a large wave of retiring baby-boomers turn their summer homes into yearround residences and put a correspondingly large strain on the aging septic infrastructure of the region –
the prospect of thousands of failing on-site septic systems leaking partially treated sewage into the
groundwater or the lake itself must give one pause.
What’s to be Done?
Of course, the indefinite use of existing septic systems is simply not feasible. Whether sooner or later and
whether with regard to environmental and community health concerns or with regard to the concerns of
the pocketbook, the Lake of the Ozarks region must update its sewage treatment infrastructure. There are
two methods for accomplishing this: First, existing on-site septic systems can be replaced by new on-site
septic systems, either at the sole expense of the property owner or under some system in which the
government provides financial assistance. Second, regional sewer systems can be expanded and
consolidated so that more lakeside homes can easily and affordably take advantage of a centralized
sewage treatment facility(ies) [5]. Both methods will likely need to be employed.
Missouri Attorney General Chris Koster in 2010 convened a symposium for the discussion of issues
related to preserving Lake of the Ozarks water quality. In his report on the symposium, he provides 12
detailed, well-reasoned suggestions protecting the lake. Among his chief points is a call for the creation
of a regional sewer district. He argues that the cost of replacing the coming few decades’ worth of failing
on-site systems individually with new on-site systems could easily exceed $150,000,000. He asserts that,
“This figure is based upon a conservative assumption that the replacement and/or repair cost for at least
15,000 on-site systems would average $10,000.00. Many we spoke with during the symposium estimated
the average replacement cost between $15,000.00 and $30,000.00.” [5] The Attorney General believes
that a regional sewer district, eligible to receive state and federal funding, would be a more affordable and
sensible way to deal with many residences’ sewage management problems.
On the other hand, on-site systems may remain the only practical treatment systems for some
homeowners. Homeowners may be effectively isolated from a prospective regional sewer system by local
topography, or by occupying a locality with sufficiently low population density that building a sewer
would seem nonsensical or impractical [5], [14]. Modern on-site septic systems, properly installed and
maintained, can safely and reliably deal with average quantities of household sewage [12]. The problem
from a community and environmental standpoint is regulation. The Attorney General points out in his
report that the exact number of on-site septic systems in use in the lake region is not known. The number
of those systems that may already be failing is likewise hard to pin down. The state maintains functional
standards for on-site septic systems, but inspectors and health specialists may not be alerted to failing
systems unless, for instance, the disgruntled neighbor of an odiferous dysfunctional septic system calls to
complain of a violation [15]. Inspectors and officials likewise lack the authority to effectively enforce
these regulations [5], [15].
An effective mechanism for enforcing adherence of on-site septic systems to state standards is the
requirement, instituted in some Missouri counties, that owners of old on-site systems must demonstrate
that the system can pass inspection before they can legally sell the property that includes said system [5].
Such a requirement in the Lake of the Ozarks region would provide a convenient, systematic way of
gradually forcing property owners to replace or repair inadequate on-site systems, and is also among the
12 recommendations included in the Attorney General’s report.
Act Fast
As the population surrounding the Lake of the Ozarks continues to grow, the regional community and
indeed the state would be well served to act sooner rather than later to put in place more effective sewage
treatment infrastructure. Water quality remains good enough to continue to support the boating and
swimming enjoyed by so many of the lake’s visitors in the immediate future, but recent instances of
dangerously high levels of E. coli found in parts of the lake should give the lake community cause for
deep concern. Even a lakeshore supplied with the best of wastewater management systems, if heavily
populated, must fight to preserve the natural beauty of its lake, as anyone who has observed the obvious
differences between the water in an ‘urban’ lake and the water in an isolated mountain pond can attest.
Furthermore, the Lake of the Ozarks region depends on the lake’s appeal as a natural recreational
attraction for much of its economic livelihood. With this in mind, municipal, county, and state
governments should work together to replace existing sub-standard on-site sewage treatment systems with
either a regional sewer system, as outlined by the Attorney General in his report on his symposium,
‘Protecting Water Quality at the Lake of the Ozarks: An Environmental Roadmap for the Future,’ or by
providing financial incentives for residents with failing on-site systems to repair or replace their systems.
However, more than that, it is vital that ordinary citizens in the lake area take responsibility for the
foundation of their community. They must actively work to protect their lake and to understand the
forces that threaten it. Homeowners who make use of on-site septic systems should take particular care to
monitor their system and accept financial responsibility for the maintenance that it requires. Community
organizations such as the Lake of the Ozarks Watershed Alliance work to monitor and protect the lake’s
water quality [16]. The concern of the lake’s denizens for the health of their environment must keep pace
with population growth and economic development in the region.
Fig. 4 – a portion of the Lake of the Ozarks waterfront
Source: http://www.columbiamissourian.com/sto ries/2011/11/10/update-regulato rs-revise-order-buildings-molake/
References
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
U.S. Environmental Protection Agency. News Release: City Pleads Guilty to Dumping Raw
Sewage Into Lake of the Ozarks [Online]. Available:
http://www.epa.gov/compliance/resources/cases/criminal/highlights/2008/lakeozark-08-25-08.pdf
Missouri Department of Natural Resources. Lake of the Ozarks Water Quality Initiative: Report
[Online]. Available: http://www.dnr.mo.gov/loz/initiative-final.pdf
C. Blank. (2010, Jan.). Ex-DNR Official: Lake Test Results Delayed to Make Plan. Columbia
Missourian [Online]. Available: http://www.columbiamissourian.com/stories/2010/01/05/ex-dnraide-test-results-delayed-get-context/
Missouri Department of Natural Resources. Water Quality at Lake of the Ozarks [Online].
Available: http://www.dnr.mo.gov/loz/index.html
The Attorney General’s Symposium: Protecting Water Quality at Lake of the Ozarks: An
Environmental Roadmap for the Future. (2010, Aug.). Lake of the Ozarks Watershed Alliance
[Online]. Available: http://www.soslowa.org/agwhitepaper.pdf
U.S. Environmental Protection Agency. Basic Information about E. coli 0157:H7 in Drinking
Water [Online]. Available: http://water.epa.gov/drink/contaminants/basicinformation/ecoli.cfm
Sea Grant Pennsylvania. (2006). The Facts about E. coli [Online]. Available:
http://seagrant.psu.edu/publications/fs/EColi.pdf
U.S. Environmental Protection Agency. Water: Monitoring and Assessment: Fecal Bacteria
[Online]. Available: http://water.epa.gov/type/rsl/monitoring/vms511.cfm
Missouri Department of Natural Resources. Lake of the Ozarks State Park 2009 Beach Sampling
[Online]. Available: http://www.dnr.mo.gov/loz/beachstudy.htm
Missouri Department of Natural Resources. (2009). E. coli Monitoring at Lake of the Ozarks
[Online]. Available: http://www.dnr.mo.gov/env/esp/wqm/loz-ecoli-2009-oct.pdf
City of Columbia, MO. GoColumbiaMo.com. (2007). Columbia Regional Wastewater Treatment
Plant [Online]. Available: http://www.gocolumbiamo.com/PublicWorks/Sewer/wwtppg_4.php
U.S. Environmental Protection Agency. (2002, Feb.). Onsite Wastewater Treatment Systems
Manual [Online]. Available: http://www.epa.gov/owm/septic/pubs/septic_2002_osdm_all.pdf
U.S. Environmental Protection Agency. Decentralized Systems Technology Fact Sheet: Septic
System Tank [Online]. Available: http://www.epa.gov/npdes/pubs/septic_system_tank.pdf
U.S. Environmental Protection Agency. (1980, Oct.). Design Manual: Onsite Wastewater
Treatment and Disposal Systems [Online]. Available:
http://www.epa.gov/owm/septic/pubs/septic_1980_osdm_all.pdf
R. Berg and M. Reiss. (2009, Nov.). Costs Compound Septic System Problems at Lake of the
Ozarks. Columbia Missourian [Online]. Available:
http://www.columbiamissourian.com/stories/2009/11/04/septic-system-problems-stem-multiplecauses/
Lake of the Ozarks Watershed Alliance [Online]. Available: http://www.soslowa.org/