Floodwater can contain sewage, industrial waste, bacteria, and other harmful germs. Mold may also be a concern after a flood. All of these contaminants can pose severe health hazards.
Assume that all floodwaters and anything that is wet with floodwater is contaminated.
Anyone engaged in cleanup should wear respiratory protection, particularly if the cleanup occurs after the materials have dried out. A disposable particulate respirator certified by the National Institute for Occupational Safety and Health (NIOSH) will offer some protection if properly worn. The best lung protection is a respirator with chemical and particulate cartridges.
Commonly available one-strap paper dust masks, designed to keep larger particles out of the nose and mouth, typically offer little protection. The same applies to bandannas (wet or dry) tied over the mouth and nose.
Open windows and doors and use fans to circulate air during and after disinfecting, cleaning, and sanitizing products. A mixture of one-quarter cup of chlorine bleach in 1 gallon of water is an effective and readily available cleaning solution. This solution should be kept in contact with the item to be cleaned for at least one minute.
After an item is cleaned this way, it should be rinsed well, washed again with mild soap and water, and thoroughly rinsed again. Since most fabrics can’t be cleaned with bleach without fading, they may be cleaned with an ammonia product like Lysol.
Waterproof gloves are crucial safety equipment. Nitrile gloves are usually acceptable, but if hazardous chemicals are present in the water, nitrile may not provide enough protection, and more heavy-duty gloves will be needed. When working with sharp objects that may tear your gloves, heavy-duty gloves will provide more protection.
If flood water is suspected to contain hazardous chemicals, wear chemical-resistant outer clothing (Tyvek) and goggles (NOT safety glasses). Wear rubber or plastic boots and plastic (PVC rubber or nitrile) gloves, and consider duct-taping protective clothing openings to keep water out.
Wash your hands with soap and clean running water when removing gloves, especially before breaks, meals, and at the end of a work session. If you have any open cuts or sores exposed to floodwater, wash them with soap and water and apply an antibiotic ointment to discourage infection.
Seek medical attention for cuts that become infected.
Homes with Minimal Damage
If the home has minimal damage and the overflow can be cleaned up promptly, the damaged area may need to be cleaned and disinfected. This involves thoroughly washing and disinfecting the damaged area’s walls, floors, closets, and other washable contents.
In most cases, everyday household cleaning products and disinfectants will do the job if used correctly. Disinfectants and sanitizers often contain toxic substances, so read and follow all label instructions carefully. Be careful about mixing household cleaners and disinfectants since some can produce harmful vapors. For example, mixing bleach and ammonia forms the toxic gases chloramine and ammonium chloride.
If the damage was extensive or the overflow could not be cleaned up promptly, removing and replacing damaged wallboard and wall insulation should be considered to avoid indoor air quality problems later. The wallboard acts like a sponge, drawing moisture up above the water level. It becomes very fragile if it stays wet for long and will fall apart when bumped.
Suppose asbestos-containing materials are known to be present in flood debris in amounts above the safe regulation level. In that case, they must be removed per Colorado Air Quality Control Commission Regulation No. 8, Part B.
Even if the area is dried out, contaminants may have gotten up behind the drywall and dried inside. Mold can penetrate deep into soaked, porous materials such as wood, insulation, and drywall and continue to damage these materials long after the overflow event is over. Even after everything has dried out, microorganisms can be released into the air later, triggering allergic reactions when inhaled.
Wooden wall studs and sills probably won’t need to be replaced if thoroughly cleaned, disinfected, and allowed to dry correctly. Since they will be covered by new wallboards and painted, they will be removed from direct human contact.
If the walls are paneled, the bottom of each panel should be carefully pried away from the wall. A block or something similar should be used to hold the paneling bottom away from the wall sill so that the area between wall studs can drain and dry out. The paneling may have to be removed entirely to remove any wet insulation or extensive contamination behind it.
Once disinfected and dried out, the paneling can often be nailed back into place. Wastewater won’t damage concrete like wood or wallboard, but it will still soak in to some extent. Concrete walls and floors should be washed thoroughly and allowed to dry out.
If you have experienced a power outage, please review the following food safety considerations.
Throw out all food and other supplies that you suspect may have become spoiled due to a power outage or have become contaminated by floodwater, including:
Discard any perishable food that has been held at temperatures above 41°F for more than 4 hours.
Place food waste and other waste that rots or decays into plastic bags and place them in a designated area for separate collection. When in doubt, throw it out.
Foodborne illness often presents as flu-like symptoms such as nausea, vomiting, diarrhea, or fever. If you experience these symptoms, contact your healthcare provider.
Disaster Guides for Food Facilities
Use caution to avoid contact with contamination and follow rules regarding flood debris removal.
Sewage-exposed materials must be thoroughly cleaned and disinfected to reduce the risk of disease.
Soiled clothing and small throw rugs should be thoroughly washed in warm or hot water, with bleach if possible. Discard more oversized rugs and those with foam backing.
After getting wet, wall-to-wall carpeting usually does not return to its former size and has to be thrown away. If only a portion of the carpeting is damaged, a professional carpet cleaner may adequately clean it. However, the foam padding will likely have to be replaced.
Discarded items should be sealed in heavy plastic garbage bags before disposal. Your trash collection company should be contacted about removing furniture and bulky furnishings, or the homeowner can take these items directly to a landfill.
Preparing Materials for Removal
Care should be taken when handling any materials from buildings that are damaged by flood water. Protective clothing and equipment should be worn to avoid skin contact and inhalation of disturbed material. All debris should be handled in a manner that will minimize exposure to any hazardous materials that could be present in the debris.
Those participating in cleanup activities should ensure they are up to date on all vaccinations, particularly tetanus by contacting their healthcare provider.
Transporting Debris to Landfills
Landfills should be informed that materials are coming from the flood area. Contractors should consult with the Occupational Safety and Health Administration (OSHA) at 303-844-5285 to determine required training and personal protective equipment that for those handling this material.
A state-issued demolition permit is not required to remove the debris from buildings that have been partially or completely destroyed. However, the debris must be thoroughly wetted prior to handling to minimize asbestos dust.
Asbestos
If asbestos-containing materials are known to be present in flood debris in amounts greater than regulatory trigger levels, they must be removed in accordance with Colorado Air Quality Control Commission Regulation No. 8, Part B. Trigger levels for single family residential dwellings are 50 linear feet on pipes, 32 square feet on other surfaces or the volume equivalent of a 55-gallon drum. If this is not known, the material may be handled as non-asbestos flood debris and disposed of at a permitted landfill.
Permits
A state-issued demolition permit is not required to remove the debris from buildings that have been partially or completely destroyed. However, flood debris may contain unknown substances, including chemicals. Take care when handling any materials from buildings that either are partially damaged by the floods (i.e., salvageable building materials remaining) or completely destroyed (i.e., only debris remains).
All debris should be handled in a manner that will minimize potential exposure to both the people handling the material and those in the surrounding area.
If hiring a hauler, confirm they are a licensed hauler in Boulder County.
Illegal Dumping
Flood debris should not be placed on roadsides as it will not be collected. Placing debris on the roadside may be considered illegal dumping, which is subject to penalty. To report illegal dumping, contact the Boulder County Sheriff’s Office at 303-441-4444.
Woody/Vegetative Material
There are several locations throughout Boulder County that accept yard waste at reduced rates. Visit the Yard Waste Drop-Off website for more information.
Open Burning of Flood Debris
The Boulder County Sheriff’s Office is asking residents to use caution before burning vegetative flood debris. Burning of flood debris can be a health hazard, and the smoke can impact air quality. Much of the flood debris is illegal to burn without a permit. For example, it is illegal to burn material that is wet or full of soil, construction debris, and/or trash. A permit is required to burn clean, dry tree branches that are less than 6 inches in diameter. To apply for a permit and to learn more, visit the Burn Permit website.
Hazardous Material
The Boulder County Hazardous Materials Management Facility (HMMF) collects household hazardous waste for free for residents of Boulder and Broomfield counties. Businesses are charged a small fee to dispose of their hazardous waste. Any products dropped off in good condition will be made available at the HMMF for use at no cost. For disposal or to pick up materials, visit:
1901 63rd Street – Unit C
Boulder, CO 80301
For more information, call 720-564-2251 or visit the Boulder County Hazardous Materials Management Facility website.
Some flood debris will be recyclable, saving residents money and landfill space. Learn more about Boulder County’s recycling center.
Electronic waste (E-waste) and other hard-to-recycle materials are accepted at EcoCycle’s CHaRM – Center for Hard-to-Recycle Materials, located at 6400 Arapahoe Road in Boulder.
Tires
Generally, tires are not accepted at landfills, but can be recycled for a small fee. Learn more about tire recycling.
Landfills
The best disposal option for flood debris that cannot be recycled or reused:
Failure to remove contaminated materials and reduce moisture and humidity after a flood can present serious long-term health risks. Standing water and wet materials are breeding grounds for microorganisms, such as viruses, bacteria, and mold. These can cause disease, trigger allergic reactions, and continue to damage materials long after the flood.
Landlords must fulfill specific legal requirements (Warranty of Habitability, CRS 38-12-503) that make a rental property fit for human habitation. Flooded buildings must be thoroughly dried, and evaluations must be conducted during and after remediation. Property managers should conduct a visual inspection and document remediation efforts to ensure properties have been properly remediated to prevent mold health problems.
Environmental Sampling
Environmental sampling for mold can help to determine the extent of the problem, the location of mold, and the quality of the remediation. However, sampling for mold cannot be used to determine if a building is “safe” because there are no quantitative, health-based guidelines that describe “safe” levels for microbial exposure to mold. Instead, property owners and managers should conduct a visual inspection and document remediation efforts to ensure appropriate steps have been taken to prevent mold health problems.
Review these resources for guidance on what to look for and steps to take to ensure your home is safe:
Consider the state of your septic system once flood water has receded. This will help maintain clean, healthy waters in Boulder County. Septic systems, also known as onsite wastewater treatment systems (OWTS), are our country’s second most frequently cited source of groundwater contamination. Unapproved, aging, and failing septic systems significantly impact the quality and safety of our water supply.
If your property was flooded, please walk the area of your onsite wastewater treatment system (OWTS) and look for signs of system failure. If Boulder County approves your OWTS, you can find the permit and final drawing of the system online. If you identify damage to your OWTS, repairs may be necessary. Please contact our office for further guidance at 303-441-1564.
Additional Guidance
After assessing your OWS, you may still have questions regarding the functionality of your system. BCPH Water Quality Inspectors are available to counsel you over the phone and discuss your assessment results. Our inspectors may be available to visit your site and provide further guidance if necessary.
Learn More
Water wells have been destroyed or compromised due to recent flooding. This may result in a need to:
Water from flooded wells should be considered contaminated. Do not use the water from a flooded well for drinking, cooking, washing dishes, making ice, brushing teeth, or even bathing until you have confirmed that it is safe.
Residents who are concerned about their well water should follow these steps:
Well Water Testing
Boulder County Public Health no longer offers water testing services.
Residents can disinfect water using bleach. Bleach will kill some, but not all, types of disease-causing organisms.
Chlorine Disinfection
A chlorine rinse after dishwashing can remove any bacterial contamination until the well can be remediated. For dishwashers, set the water heater to 160°F.
Fridge filters should also be replaced if well water is contaminated.
Clean hazards away from wells before cleaning and disinfecting wells and follow these precautions:
Disinfection of Wells After an Emergency (CDC)
If a well requires replacing the existing pump, no permitting process is necessary. The Colorado Division of Water Resources recommends that well owners work with a licensed water well contractor to replace the pump.
A well may need additional repair before being operational, in addition to a new pump. If the well can be repaired and put back into use, a well permit is not needed.
If a well must be reconstructed, a permit for a replacement well must be obtained prior to redrilling the well. A licensed water well contractor can help determine whether the well can be repaired or needs to be replaced.
If a well structure cannot be rehabilitated and a new well is required, the owner must obtain a permit, and a licensed contractor must do the work.
Plastic ground liners, surface contamination, and heavily contaminated soil should be removed from the impacted area if possible. When removed, contaminated soil should be disposed of in an approved landfill. The remaining contaminated soil should be treated with a liberal application of garden lime to reduce odor and enhance the degradation of the organic matter.
If the contaminated area is in the open, it should either be covered with clean dirt or temporarily fenced off to prevent accidental contact with the lime and any remaining contamination. After a day or two, mix the lime in with a rake and use a sprinkler or hose to water the lime and any remaining residues into the soil. Prevent water or soil from entering stormwater by containing it onsite or disposing of it in an approved landfill or wastewater dump station. Let the area dry in the sun, if possible, before allowing access.
Excavated soils may be remediated onsite by treatment with garden lime, which should be turned over frequently to provide oxygen to the naturally occurring microbes in the soil that degrade the organic material. If onsite treatment is not possible or cannot be accomplished without creating a nuisance condition, contaminated soils and other materials removed from the impacted area may be disposed of at any landfill willing to accept them.
Play Area Safety & Health
Flood waters can carry dangerous chemicals or materials (e.g. broken glass and metal) and may contain bacteria that can cause illness. Outdoor play equipment and loose materials that come in contact with flood waters can harbor these organisms, even after flood waters recede, making them unsafe. Below are some simple guidelines to help protect children at play following a flood:
Flood waters can carry dangerous materials and may contain bacteria. It is best to till the soil and wait 90 days between flooding and planting fruits and vegetables and/or test the soil before planting (see below). This allows time for anything deposited on the soil to be exposed to sunlight, rain, air, and other conditions that reduce the likelihood that bacteria and viruses will still be present. Chemical substances in flood water were likely diluted and should be at low levels.
If you don’t see signs of chemical contamination, it is likely not a concern.
Signs include:
If your garden area comes in contact with flood waters or sediment or you think your planting area may contain high levels of chemicals, the only way to know for sure is to have the soil tested by a certified laboratory. This can be expensive, however, and test results can be hard to interpret. So, it is best to avoid planting in those areas until you are sure it is safe.
If you do decide to test, the following Colorado labs offer relevant soil testing:
Sewage backups present unpleasant odor problems and may cause property damage and unhealthy living conditions. Untreated sewage contains disease-causing organisms such as bacteria, viruses, and parasites. Contact with contaminated water can cause skin infections and rashes. If ingested accidentally via improperly cleaned hands or food preparation surfaces, these contaminants can cause nausea, abdominal pain, vomiting, and diarrhea.
Mold growth associated with wet and humid conditions may also result in respiratory infections and allergic reactions. The drying-out process can take several weeks in an enclosed area such as a basement or crawl space, and microorganism growth will continue as long as the humidity remains high. A musty odor can remain long after the sewage overflows if the damaged area is not cleaned and dried out properly.
If there is a broken sewer line outside the home or in a crawl space under the home, the first step to cleaning it up is to put on protective clothing such as:
