The Dangers of Floodwater

A flood can be a dangerous experience, whether it’s confined to your basement or a large-scale weather event. Large-scale flooding carries the obvious risk of drowning, but even small home floods can result in dangerous electrical hazards and contamination risks.

What’s Really in Floodwater?

What’s in floodwater depends on the source of the flood. A basement flood might occur due to stormwater or sewage backups, often including potentially harmful bacteria, parasites, and microorganisms.

Large-scale floods include floodwaters from heavy rain, hurricanes, and rivers swollen with rainfall or thawed snow. In such cases, flood waters can come with a wide range of potential hazards, including: 

• Human and livestock waste
• Drowned animals
• Household, medical, and industrial waste
• Coal ash waste 
• Germs and biological contaminants
• Live animals, including rodents, snakes, and other wildlife
• Lumber, fallen trees, and other large debris

Physical Dangers of Floods

Flash floods are particularly dangerous. According to the National Highway Traffic Safety Administration, just 12 inches of rushing water can carry away most cars, while 2 feet of rushing water can carry away trucks and SUVs. Avoid wading or swimming in floodwaters for the same reasons. 

Electrocution risks from downed power lines or water-damaged home wiring are one of the main dangers of floods. Avoid areas of downed power lines, and never go into a flooded basement until a licensed electrician or emergency worker (such as from the fire department or utility company) has fully disconnected your home from the grid. Even if you’ve lost power during a storm, a neighbor running a generator could be enough to back feed electricity into your home and put you at risk for electrocution.

Debris in flood water can cause injuries or entangle you, increasing the risk of drowning. Floods can displace potentially dangerous wildlife as diverse as rats, snakes, coyotes, deer, and alligators. Avoid all contact with wild animals after a flood to avoid injury. In the aftermath of a flood, local mosquito populations may increase and spread disease. 

An often overlooked floodwater threat is hypothermia. Even in warm climates, hypothermia can develop rapidly after heavy rain or floodwater exposure. Early signs of hypothermia include shivering, pale skin, and difficulty thinking clearly. Slurred speech and increasing mental confusion can occur, followed by loss of consciousness or hallucinations. 

Severe hypothermia can be fatal. Keep the affected individual warm and dry, and call for medical assistance immediately. Use gradual warming techniques, as warming someone up too quickly can also be harmful. (For a more complete explanation of hypothermia, we recommend the Mayo Clinic.)

Health Hazards in Floodwater

Contaminated flood water poses a serious threat to your health. In general, you might encounter three types of floodwater. Clean water and greywater floods are usually confined to the home, while blackwater floods can happen at home and on a larger scale, such as the widespread flooding after a hurricane or other severe weather events.

Clean water describes floodwater that does not pose an immediate health threat. Clean water floods can result from malfunctioning appliances, toilet holding tanks, and melting snow and rainwater. Clean water home floods are generally safe to clean up once the flooded area is deemed safe by an electrician, but standing clean water can become greywater in as little as 48 hours.

Greywater, or sullage, refers to wastewater not contaminated with fecal matter. Greywater could include water from bathtubs and showers, washing machines, dishwashers, and sinks. It generally contains fewer pathogens than blackwater and can be reused for non-potable purposes, such as toilet flushing. Greywater still contains small amounts of contaminants and can induce illness if ingested.

Greywater flooding can be caused by weather events, overflowing plumbing fixtures or appliances, or a broken pipe. If you experience a home flood with greywater, take caution when beginning the cleaning process. Wear protective gear, and keep children, pets, and individuals with compromised immune systems away from the flooded area. If the flood is extensive, such as several inches of standing water in the basement, hire professionals to clean up and decontaminate the area safely. Cleanup must begin immediately: greywater can become blackwater in as little as 48 hours.

Blackwater refers to wastewater contaminated with human waste and raw sewage. The citywide floods we often see on television are blackwater. Blackwater is a haven for dangerous bacteria and pathogens that must fully decompose before being released into the environment. It can also be contaminated with dissolved chemicals and particulates, making contact even more dangerous.

When it comes to flood water, blackwater is the most dangerous and destructive. Because of the grossly unsanitary conditions of the water, porous and absorbent items such as carpets, upholstery, and drywall are often unsalvageable. Contact with blackwater via ingestion or skin contact can cause illness in humans and pets.

Safety Tips when Dealing with a Flood

• Know your evacuation routes and make an evacuation plan. 
• Pack a go-bag with essentials, including clean clothing, food, bottled water, and medication. 
• Buy a hand-cranked or solar-powered radio to monitor flood watches, warnings, and evacuation orders.
• Monitor areas that have had water damage in the past.
• Keep the number of your local Roto-Rooter on hand at all times! Save the number of your local Roto-Rooter plumbing expert and post it near areas most susceptible to water damage. Or call our national toll-free number: 1-800-GET-ROTO, which automatically routes you to your local Roto-Rooter location.
• Inspect pipes, water shutoff valves, appliance connections, and hoses regularly for potential leaks.
• In areas prone to flood damage, install flood alarms to help with early detection and to prevent damage.
• Purchase additional flood insurance for your home or business. 

How Floodwater Damages Plumbing Systems

Floodwater can cause severe damage to plumbing systems, including increasing pressure within pipes that can lead to leaks or burst pipes. Blockages due to flood debris are possible, potentially leading to sewer line backups. Floodwater can cause foundation damage and soil shifting, damaging underground pipes. 

Warning Signs to Watch For After a Flood

Stay vigilant in the aftermath of a flood. Watch for:

• Musty odors
• Water stains on walls, floors, or ceilings
• Peeling paint
• Warped floors or floorboards
• Soft, “spongy” floors or walls
• Mold growth
• Persistent drain clogs
• Standing water
• Sinkholes in your yard
• Cracked or damaged foundations 
• Unexplained utility bill increases, which may indicate hidden leaks

The dangers of floods should never be underestimated. Stay safe, take precautions when possible, and trust Roto-Rooter to help with floodwater damage. Our professional plumbers are on call 24/7 to help you respond to and recover from floods.