Collecting rainwater has long been a popular choice for drinking and use around the home. Whether you’re aiming to cut down on water bills, prepare for dry seasons, or simply reduce your environmental footprint, a rainwater tank is a fantastic asset. Rainwater¹ collected from a properly maintained system in Australia is generally safe to drink. However, the water from these tanks can sometimes come with unexpected qualities, such as being dirty, hard, or soft. In this post, we’ll explore these potential issues, their causes, and how to ensure your rainwater remains clean and safe for various uses.

1. Why Rainwater Can Be Dirty

When we think of rainwater, we often imagine pure, clean water falling from the sky. While rainwater itself is generally clean, it can pick up contaminants as it makes its way into your tank. Here are some common reasons why your rainwater may become dirty:

• Debris from Roofs: Leaves, twigs, and dust can accumulate on your roof and wash into the rainwater tank when it rains. This debris can make your water look cloudy or even muddy.
• Animal Droppings: Birds, lizards, and other animals may leave droppings on your roof, which can be washed into your tank, introducing bacteria and pathogens.
• Atmospheric Pollutants: Depending on where you live, rain can carry pollutants from the air, such as dust, pollen, and industrial emissions, which may end up in your tank.
• Algae Growth: In tanks exposed to sunlight, algae can begin to grow, turning your water green and affecting its smell and taste.

How to Keep Rainwater Clean:

• Use a Gutter Guard and First-Flush Diverter: Installing gutter guards or rain heads will reduce the amount of leaves and debris entering your system. A first-flush diverter directs the initial rainfall away from your tank, allowing the first, dirtiest water to be discarded.
• Regular Cleaning and Maintenance: Clean your tank, gutters, and roof regularly to prevent buildup of contaminants.
• Install Filters: Filters at different stages, such as pre-tank and post-tank, can help reduce pollutants and debris in your water.

2. Is Rainwater Hard or Soft?

Rainwater is typically soft water, meaning it has a low mineral content compared to groundwater. Hard water contains higher concentrations of calcium and magnesium ions, which cause scaling in pipes, faucets, and appliances. Here’s a closer look at the characteristics of rainwater in this regard:

• Soft Water Characteristics: Rainwater doesn’t naturally contain the minerals that cause water hardness, so it’s softer than tap water or groundwater. This makes rainwater great for household uses like laundry, as it lathers well with soap and doesn’t leave mineral deposits.
• Becoming Hard Over Time: While rainwater is initially soft, if your tank has cement, limestone, or concrete materials, the water can leach minerals from these surfaces over time. This can make the water slightly harder, although it’s usually not enough to create scaling problems.

How to Maintain Soft Water in Your Rainwater Tank:

• Choose Tank Materials Wisely: Opt for plastic (polyethylene) tanks if you want to avoid mineral leaching, which can lead to increased hardness in your water.
• Regular Testing: If you notice signs of hardness, like spots on dishes, consider testing your water to understand its mineral content. Basic home test kits can measure hardness, or you can send a sample to a lab for more detailed analysis.

3. How to Test and Improve the Quality of Your Rainwater

Regular water testing is the best way to monitor your rainwater quality. Testing can alert you to high levels of pollutants, bacteria, or minerals that might affect your water's cleanliness or hardness.

• pH Levels: Soft rainwater is typically slightly acidic. If the pH is too low, consider adding a neutralising filter to prevent corrosion in metal pipes.
• Mineral Content: A basic test will show you the levels of calcium, magnesium, and other minerals, helping you determine if your water is becoming harder over time.
• Bacterial Testing: For tanks used as a drinking water source, bacterial testing is essential. UV filters or chlorination may be necessary to ensure safety.

Final Thoughts

Rainwater tanks offer an efficient, eco-friendly way to manage water resources, but maintaining water quality is essential. By taking proactive steps to manage debris, monitor tank conditions, and keep contaminants at bay, you can enjoy the benefits of clean, soft rainwater for years to come. Whether you’re watering your garden, doing laundry, or considering rainwater for drinking purposes, regular upkeep and testing will ensure your rainwater remains a valuable asset. To learn more about finding the right rainwater tank for your home, business, or property, contact our friendly team today.