Mold

In order to maintain a healthy, mold-free indoor environment, water leaks should be addressed immediately. Water leaks can cause mold growth on materials, like the paper backing of drywall, carpeting, or wood products, in as little as 48 hours, causing health problems for your tenants and property damage for you.

Good Practice Recommendations for Mold

1. Immediately fix the cause of the water.
2. Fully dry water-damaged areas and items within 48 hours to prevent mold growth.
3. Use stainless steel, braided water fill line hoses for washing machine installations. Instruct tenants to shut off the hot and cold water feeds to the washer when leaving the apartment for extended periods of time.
4. Inspect areas with high potential for water damage frequently:
   • Inside walls located at an exterior windows
   • Bathroom shower walls
   • Kitchen sink area
   • Rooms containing washing machines
5. If present, inspect landscaping sprinkler systems frequently for proper operation.
6. Always vent clothes dryers to the outdoors.
7. Even if not required, provide outdoor exhaust to bathrooms containing showers.
8. Prior to extensive renovations due to water damage, perform analyses of the asbestos and lead content of building materials used in the house. Improper renovations that do not consider asbestos content of building materials and the lead content of paint can lead to contamination and violation of asbestos control regulations.
   • Learn more about asbestos
   • Learn more about lead
9. Conduct a long-term radon evaluation of the building. Radon is the second leading cause of lung cancer in America (after smoking).
   • Learn more about radon

Property Manager & Landlord Requirements

Landlords are required to fulfill certain legal requirements (Warranty of Habitability, CRS 38-12-503) that make a rental property fit for human habitation. Buildings that have been flooded 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.

Boulder County Public Health does not conduct mold inspections or testing in homes, rental units, or commercial buildings. Mold remediation should be done by an industrial hygienist or environmental consultant.

Documentation of Mold Remediation Efforts

• English
• Spanish

Mold Contamination and Landlords

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.

Boulder County Public Health does not conduct mold inspections or testing in homes, rental units, or commercial buildings. Contact an industrial hygienist or environmental consultant.

The best practice when dealing with mold is to stop the water leak and then clean the mold.

Mold Contamination and Renters

Note: Boulder County Public Health (BCPH) is not a legal service and does not have the authority to enforce contracts or building codes.

Easy Steps to Prevent or Repair Mold Problems

1. Before signing the lease, inspect the home for any water leaks, damage, or mold. Take your time to look around. If the house smells like there is a mold problem, there probably is.
   • Mold Photo Gallery
2. If you see water leaks, damage, or mold, ask the landlord to repair the problem before you rent.
   • Place a line in your rental agreement that says water intrusion will be stopped and mold cleaned up before the move-in date.
   • Do not move in if the problems are not fixed.
3. After moving in, continue to check for leaks and mold. If you see leaks (like a leaking roof or pipes), prepare a written list of problems you can immediately give the landlord.
   • Delays may result in more damage.
   • Some leases require that water damage be reported immediately.
   • Understand that repairs take time to complete.
   • Keep records of written requests for repairs and ask for all verbal agreements to be put in writing. (i.e. get a written schedule of when leaks will be fixed and repairs done.)
4. If repairs are not made after repeated requests and water intrusion/mold continues to be a problem, you may want to seek legal advice.

Remember, a mold-free home is in the landlord and tenant’s best interest. Water damage can require extensive, expensive repairs. Early detection is also in the interest of both the tenant and the landlord. Communicate with your landlord when you have problems with a rental property.

Environmental Sampling

Environmental sampling for mold can help determine the extent of the problem, the mold’s location, and the remediation’s quality. 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. Boulder County Public Health does not conduct mold inspections or testing in homes, rental units, or commercial buildings. Contact an industrial hygienist or environmental consultant.

Assessing the Problem

Substantial mold growth indoors can be a reservoir for mold contamination, potentially causing adverse health effects. Under optimal conditions, water intrusion can cause mold growth on materials, like the paper backing of drywall, carpeting, or wood products, in as little as 48 hours.

Since mold spores can be found in the air practically anywhere on Earth, the impact on health depends upon whether mold growth and the resultant mold spores and particles have grown indoors. Comparing mold spore levels indoors and outdoors may be helpful in determining risk, but air sampling can be costly.

An alternative to air sampling is to inspect the building, identify materials that were subjected to moisture or water intrusion, report the potential for mold growth, and recommend removal and repair.

Additional Resources for Renters

City of Boulder Mediation Service

For residents living in the city of Boulder. The City of Boulder Mediation Program provides mediation between landlord and tenant on housing issues. 303-441-4364.

City of Longmont Community Mediation

Residents of the city of Longmont can access Longmont’s Community Mediation services for issues between landlords and renters. 303-651-8444.

Boulder County Community Assistance Mediation Program (CAMP)

For residents living inside Boulder County but outside the cities of Boulder and Longmont, the Boulder County Community Assistance Mediation Program provides free mediation services for those involved in disputes.

Hope House of Colorado Community Housing Services

For all residents living in the State of Colorado, Hope House of Colorado Community Housing Services helps people understand their rights in a landlord/tenant dispute.

CU Off-Campus Student Services (OCSS)

Current University of Colorado students can receive free legal advice about housing concerns via CU Off-Campus Student Services.

Clean Up Mold and Fix the Problem

Water causes mold to grow in some building materials within as little as 48 hours. Building materials, like the backside of drywall or carpet and padding, can grow mold and bacteria, while ceramic tile and concrete floors cannot. Because mold grows quickly, it is important to repair the source of the water leak immediately and remove all moldy building materials.

Control Potential Water Sources

To prevent mold growth, control the places where water can get in and cause damage. Water can enter the home and cause damage from the following sources:

• Outdoors – rain, snow, or plant irrigation systems allow water in through leaking roofs, windows, siding, crawl spaces, etc.
• Indoors – bathing/showering, cooking, indoor plants, or pet urine
• Building sources – excessive moisture allowed within a building during the construction/renovation process; temporary holes in roofing, walls, or siding
• Leaks – plumbing or washing machine leaks (especially from the hot water line), dishwasher backups or pump failure, leaking ice maker water line to refrigerators, toilet overflows, slow water pipe leaks inside walls, etc.
• Condensation – from poorly insulated windows or cold surfaces

Dry Wet Areas Within 48 Hours

Mold and bacteria grow quickly, and it is important to repair leaks as soon as possible. Microbe growth can increase significantly in as little as 48 hours, so it is important to dry water-damaged areas within 48 hours to prevent mold growth. Without moisture, mold cannot grow and will not be a health concern. If building materials that support mold and bacterial growth are not dried immediately, they must be removed. If not, mold growth occurs, and although the material is dried, the mold spores remain.

What to Clean

Before cleanup, stop the source of water. Otherwise, the mold will grow back.

• Non-porous materials like ceramic tile and plastics
• Semi-porous material, like wood and concrete, if they are structurally sound
• Valuable items, such as picture albums or books, may possibly be restored by a professional

What to Throw Out

Porous materials, like drywall, carpet, padding, ceiling tiles, or insulation that have been wet for longer than 48 hours should be removed and disposed of.

• Drywall tends to remain wet, especially the bottom portion, even after the source of water is gone. If drywall has been wet for longer than two days, remove the affected drywall approximately 3 feet up from the floor or 1 foot beyond the water line.
• If removing drywall, isolate the room or rooms where the demolition is being performed with plastic, and use a fan to create negative pressure in the room.

How to Clean

• Use a soap, detergent, or 10% chlorine bleach solution.
• Use the gentlest cleaning method that effectively removes the mold and limits the dust created.
• After the area is cleaned, dry it thoroughly.
• Vacuum the cleaned materials with a high-efficiency particulate (HEPA) air cleaner to remove difficult-to-see mold particles.
• If you are sensitive to mold, you can use a “Type N-95” respirator to limit your exposure to airborne mold during cleaning. These are available at many hardware stores and on the Internet.
• If mold reappears, the source of the water has not been eliminated.
• Consider hiring an environmental health professional or industrial hygienist to define the problem and a trained contractor to clean it up. Checking references to make sure the contractor has experience cleaning up mold.
• Contact an industrial hygienist or environmental consultant.
• Ask the contractor to follow the recommendations of one of the following:
  • The New York City Department of Health & Mental Hygiene, Guidelines on Assessment & Remediation of Fungi in Indoor Environments
  • The Environmental Protection Agency Mold Remediation in Schools and Commercial Buildings

Mold Cleanup Quality Assurance

Measures to ensure the quality and effectiveness of remediation should be taken regardless of the project size. Evaluations both during and after remediation should be conducted to confirm the efficacy of remedial work, particularly for large-scale remediation. At a minimum, these quality assurance indicators should be followed and documented:

• Identifying and eliminating the underlying moisture problem.
• Ensuring that isolation of the work area is appropriate and effective.
• Performing mold removal and worksite cleanup according to the site-specific plan.
• Properly addressing any additional moisture or mold damage discovered during remediation.
• Upon completion of remediation, ensure that surfaces are free from visible dust and debris.
• If environmental sampling was performed, ensure that the results were evaluated by a trained building or environmental health professional.

For more information, see the Environmental Protection Agency (EPA) document Mold Remediation in Schools and Commercial Buildings.

Prevent Mold Contamination

Control Potential Water Sources

To prevent mold growth, control the places where water can get in and cause damage. Water can enter the home and cause damage from the following sources:

• Outdoors – rain, snow, or plant irrigation systems allow water in through leaking roofs, windows, siding, crawl spaces, etc.
• Indoors – bathing/showering, cooking, indoor plants, or pet urine
• Building sources – excessive moisture allowed within a building during the construction/renovation process; temporary holes in roofing, walls, or siding
• Leaks – plumbing or washing machine leaks (especially from the hot water line), dishwasher backups or pump failure, leaking ice maker water line to refrigerators, toilet overflows, slow water pipe leaks inside walls, etc.
• Condensation – from poorly insulated windows or cold surfaces

Fixing Mold Contamination after a Flood

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.