A Taste of What's Inside
This chapter explores the hidden biological contaminants that can affect your stored water. We’ll look into the most common culprits—bacteria, viruses, and algae—and discuss how they can impact your water’s safety and usability. We’ll also provide practical guidance on testing and prevention.
Bacteria and Viruses
Bacteria are single-celled microorganisms found in virtually every environment on Earth. While many bacteria are harmless and some are even beneficial, many are known to cause severe illness in humans, livestock, and plant life. These harmful bacteria, known as pathogens, can threaten those who drink or come into contact with the water.
Viruses are even smaller than bacteria and can’t reproduce on their own. Instead, a virus must invade the cells of a living organism and hijack the cell’s machinery to create copies of itself.
Both bacteria and viruses can contaminate your stored water. They can enter through contaminated source water, direct contact with unclean equipment, or even airborne particles. Effective water treatment and storage practices are the only way to keep your stored water safe.
Health Risks of Bacteria and Viruses
Some common pathogens include bacteria like E. coli, Salmonella, and the Norovirus, which can cause diarrhea, vomiting, and stomach cramps. Adenoviruses can cause multiple illnesses, including respiratory infections, gastroenteritis, and conjunctivitis (pink eye). While they typically cause only mild to moderate disease, adenoviruses can sometimes lead to more severe complications, such as pneumonia or bronchitis, particularly in vulnerable individuals.
Viruses can be more resistant to disinfection than bacteria, so additional treatment methods may be necessary, especially during emergencies.
Algae
Algae are simple, plant-like organisms that thrive in water. While essential to natural ecosystems, they can be simultaneously a practical nuisance and a health hazard in your water storage. Algae growth is often triggered by excess nutrients like nitrates and phosphates, warm temperatures, and sunlight. Many algae are microscopic, making them difficult to see and filter out.
If your source water is contaminated with algae, removing them entirely from your stored water can be challenging, even with treatment. This fact is especially concerning if you use surface water or rainwater, which are more susceptible to algae growth.
Why Algae is a Problem
Algae can cause several issues in your stored water, starting with the compounds it produces that give your water a musty, earthy taste and smell and make it unappealing for drinking, cooking, or other household uses.
Some algae, particularly cyanobacteria (also known as blue-green algae), produce harmful toxins that can cause problems ranging from skin irritation and gastrointestinal problems to more severe neurological or liver damage in humans. These toxins can also be absorbed by crops and accumulate in livestock, eventually affecting your health and safety even if you’re not drinking the water directly. So, if you plan to use your stored water for irrigation, it’s crucial to ensure it’s free from harmful algae and their toxins.
Other Biological Contaminants
As if there weren’t enough things to worry about, other microscopic pathogens, such as protozoa and parasites, can also lurk in your stored water.
Protozoa
Protozoa are single-celled organisms that are larger and more complex than bacteria. Some protozoa are also parasites, meaning they live on or in a host organism and cause disease. Protozoa can enter water sources through fecal contamination from humans or animals, often associated with sewage overflow from flooding or farm runoff.
One example is Giardia lamblia, which causes Giardiasis. This intestinal infection can lead to persistent diarrhea, abdominal cramps, bloating, and fatigue. While usually not life-threatening, Giardiasis can be challenging to treat and may cause long-term complications.
Parasitic Worms
Parasites live on or in a host organism and obtain nutrients at the host’s expense. Some parasitic worms can contaminate water sources directly through animal or human fecal contamination or an intermediate host and cause human illness. One example is schistosomiasis, a disease caused by parasitic worms that can cause abdominal pain, diarrhea, and blood in the stool or urine. In severe cases, it can cause damage to the liver, intestines, lungs, and bladder.
Sources of Biological Contamination
Even if you start with pristine water, biological contaminants can still sneak into your stored water through several mechanisms.
Source Water
Whether it’s rainwater, well water, or municipal water, your source can already contain bacteria, viruses, and other microorganisms. Well water can be contaminated by nearby septic systems or livestock. Rainwater can pick up contaminants as it flows over your roof. Surface water sources, like rivers and lakes, can be contaminated with agricultural runoff or sewage. Even municipal water systems can fail from time to time.
Airborne Particles
It might surprise you that bacteria, viruses, and even algae spores can stick to dust particles, pollen, or tiny droplets in the air. And just like dust seems to magically find its way onto every surface in your home, these airborne contaminants can settle on the water’s surface or sneak in through the tiniest openings in your storage system.
Biofilms
Biofilms are communities of bacteria and other microorganisms that form slimy layers inside your water storage systems. They’re a persistent contamination source but can be stubbornly difficult to remove.
Testing for Biological Contamination
Biological testing is mandatory if you’re using your stored water for drinking, cooking, or household purposes. Regular testing can help you identify potential problems early on and take corrective action before any harm is done. Testing can reveal the presence of pathogens like bacteria, viruses, and other microorganisms that are invisible to the naked eye.
Test your water source before setting up your storage system to establish a baseline. After that, test your stored water regularly, especially drinking water. A good rule of thumb is to test at least every six months or more frequently if you notice any changes in the water’s appearance, taste, or odor. Also, test after potential contamination events, such as flooding or power outages.
DIY home test kits can provide a basic assessment of water quality. They typically test for coliform bacteria, which are indicators of fecal contamination. For a more thorough analysis, send water samples to a certified laboratory. Labs can test for a broader range of contaminants, including specific bacteria, viruses, and parasites.
If your test results indicate contamination, treat the water immediately (see Chapter 7 for more information) or find an alternate water source. Consult with a water quality professional or your local health department for guidance on interpreting test results and addressing contamination.
Preventing Biological Contamination
As they say, an ounce of prevention is worth a pound of cure, and preventing biological contamination is the most effective way to ensure your stored water is safe and usable. Here’s how to keep those microscopic intruders at bay
First, start with the cleanest water source you can. Well water should be tested regularly, and if you’re collecting rainwater, keep your roof and gutters clean. Filter surface water before it enters your storage, and seal your tank or cistern with a tight-fitting cover to keep out dust, debris, critters, and curious hands.
Wash your hands before touching your water storage system, and always use clean tools and equipment. If you need to get inside your tank, wear gloves. Regularly clean and disinfect your water storage tank to prevent gunk from building up, and keep an eye out for any signs of contamination, like weird colors, funky smells, or slimy stuff (that’s biofilm!).
A high-quality liner in your tank can help prevent contamination from the tank itself. Just make sure it’s certified for drinking water and plays nicely with your tank material. And don’t let algae take over your water: limit nutrients, block sunlight, and keep the water moving to prevent those green guys from crashing the party.
Putting a Lid on It
This chapter has shown how bacteria, viruses, and other microorganisms can contaminate your water stores and followed up with valuable information for keeping your water clean and safe. So, now that we’ve covered the essentials of biologics, let’s move on to Chapter 5, where we can look into the threats coming from chemical contaminants.
