The final Department of Public Health and Environment report on the outbreak was released Wednesday.
The report found animal waste likely contaminated an in-ground storage tank that had been identified as a problem in 1997.
The 2008 outbreak included 442 reported cases of illness, but state health officials estimate as many as 1,300 of the towns 8,900 residents were sickened.
One death was associated with the outbreak.
Ron Falco, manager of the Safe Drinking Water program at the state health department, says the animal waste contamination in the concrete storage tank was the most likely cause.
Falco says state health investigators were not notified of a 1997 inspection provided to the city by a private company.
The inspection report recommended routine inspections to monitor "cracking and problem with the corners of the tank," the state report said.
Falco told 9Wants to Know Alamosa did not share the report with the state and could not provide any evidence that follow-up inspections occurred in the 11 years between the inspection and the outbreak.
State inspections "did not focus on storage tanks and distribution piping," the report said.
Falco says if Alamosa had provided records of the problems, state inspectors could have issued a recommendation or a requirement for a repair.
"If we'd had those records, we would have reviewed them," Falco said.
"Hindsight is 20-20," Falco added. "It's easy to say now we would have required that."
Alamosa Public Works Director Don Koskelin did not immediately return a call requesting comment.
The deteriorating tank was ripe for contamination because Alamosa did not chlorinate its water at the time of the outbreak.
"...only a small quantity of bird or animal feces contamination may have led to the salmonella outbreak," the report read. "This kind of outbreak may have been very difficult to prevent in a system that did not chlorinate its water."
Alamosa had a public drinking water system disinfection waiver that allowed it to avoid chlorination.
Since the 2008 outbreak, the state health department has withdrawn 72 of 126 disinfection waivers statewide.
Currently, 17 community water systems like cities and towns have waivers and 37 non-community water systems like rural restaurants, campgrounds and schools have waivers.
Alamosa began chlorinating its water following the outbreak.
The read the entire 65-page state report detailing the 18-month investigation, click here.
To discuss this story or to suggest another story idea, e-mail investigative reporter Kyle Clark.
Community water systems that have an active disinfection waiver as of 11/18/09:
Public Water System Name, County
FALLS CREEK RANCH #1, LA PLATA
FALLS CREEK RANCH #2, LA PLATA
FT GARLAND WSD, COSTILLA
GARCIA DOMESTIC WUA, COSTILLA
KV HOV INC, SAGUACHE
LA JARA, CONEJOS
MESA CORTINA WSD, SUMMIT
MID COLORADO INVESTMENT, TELLER
MOUNTAIN MUTUAL WA, TELLER
MT PRINCETON RV PARK AND CABINS, CHAFFEE
SAN LUIS WATER AND SANITATION DISTRICT, COSTILLA
WOODLAND WEST WATER USERS ASSOCIATION, TELLER
Non-Community/Non-Transient, Non-Community Drinking Water Systems with active waivers as of 11/18/09:
Name of Drinking Water System, County
ALPINE LODGE, CHAFFEE
AMPHITHEATER CG, OURAY
CASTLE LAKES CAMPGROUND RESORT, HINSDALE
CASTLEWOOD CANYON SP, DOUGLAS
CENTAURI HS CENTAURI MS, CONEJOS
CHALK CREEK CAMPGROUND, CHAFFEE
COLORADO INTERSTATE GAS, ADAMS
DEER CREEK CHRISTIAN CAMP, PARK
DEER VALLEY RANCH AND SUBD, CHAFFEE
ELLICOTT PLAZA, EL PASO
BROWN PALACE HOTEL, DENVER
KOA ALAMOSA, ALAMOSA
KUSKIES CAF, LOGAN
LIBERTY SCHOOL, YUMA
LONE STAR SCHOOL, WASHINGTON
LOTTIS CREEK CG, GUNNISON
LUTHERAN VALLEY RETREAT, TELLER
MIAMI YODER SCHOOL DIST JT60, EL PASO
ONE MILE CG, GUNNISON
OUTHOUSE N RESTAURANT AREA, ALAMOSA
REPUBLIC PAPERBOARD, ADAMS
ROSY LANE CG, GUNNISON
ROXBOROUGH STATE PARK, DOUGLAS
SACRED HEART RETREAT JESUITS, DOUGLAS
SANGRE DE CRISTO JR SR HIGH, ALAMOSA
SARGENT ELEM SCHOOL RE33, RIO GRANDE
SARGENT HS RE 33J, RIO GRANDE
SAWMILL GULCH CG, GRAND
ST. LOUIS CREEK CG NO. 1, EAST GRAND
SUGAR LOAFIN CAMPGROUND, LAKE
SUNSHINE CG, SAN MIGUEL
TRAPPERS LAKE CG, GARFIELD
VALLECITO RESORT, LA PLATA
VALLEY VIEW HOT SPRINGS, SAGUACHE
WILDERNESS RANCH YOUNG LIFE, MINERAL
WIN MAR COTTAGES, LAKE
YOUNG LIFE TRAIL WEST LODGE, CHAFFEE
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