A house’s kitchen must be the busiest throughout the day where cooking breakfast, lunch and dinner happen. Ingredients, utensils and work surfaces must be cleaned and washed after every meal, not to mention the mounds of kitchenware that need cleaning after. If one is careless, the kitchen can be a place where a lot of water can be wasted—and where a lot of money (from wasting that water) can be wasted.
Since the monsoon season is upon us, you’re thinking of installing a rainwater collection and tank system on your property and connect that line to your kitchen, either as your main source of water or your backup. This is necessarily not a bad idea as you save some money from municipal water fees. But before even considering that, is rainwater considered safe for kitchen use?
The nature of rainwater
Collected as is, rainwater does not have dissolved solids but does contain a combination of dissolved gases like carbon, nitrogen and sulphur oxides. This results in a naturally acidic water with a pH value of around 5.5–5.6. Additionally, in regions near the coast, rainwater may contain trace amounts of sodium chloride—a.k.a., salt—due to sea spray and the water cycle (i.e., the sun absorbing water from the ocean). That said, rainwater is acidic, virtually has no mineral content and may be unsafe when used with calcium-containing materials like concrete rainwater tanks and some metals in domestic plumbing.
Furthermore, rainwater can pick up unsafe contaminants like animal faeces, atmospheric pollution, corroding and eroding roofing materials, algae, mould, etc. Therefore, there is concern among city and town councils over the safety and potability of untreated, unprocessed rainwater and whether or not they can be used as drinking water or water used in food preparation. Some councils even apply strict rules that only limit rainwater usage to toilet flushing, laundry and irrigation, among others.
Should I use rainwater stored in tanks for kitchen use?
Whether you use concrete, plastic or steel tanks, the answer is, plainly, yes and no. Yes, you can use the stored rainwater from your tank to clean your kitchen—that is, for washing and cleaning non–food preparation work surfaces, mopping floors, cleaning rags, etc. However, you cannot use untreated rainwater in food preparation and cleaning your kitchenware, utensils, etc.
Just to be safe, consult with your local legislation on the limitations of stored rainwater use. Make sure you installed the proper rainwater collection system (suitable roofing materials for collecting rainwater, debris screen on gutters, pipes, first flush diverters, etc.). Even then you’d have to boil the water so you can safely use it in food preparation to make sure you kill all bacteria present in the stored rainwater.
Which rainwater tank should I use for storing rainwater for kitchen use?
Generally, above-ground or underground rainwater tanks should be good as rainwater tanks. Let’s see which one is best for kitchens:
Slimline poly plastic rainwater tanks made of food-grade plastic are most popular for smaller homes as they can be cheap, lightweight and could be attached and connected directly to your kitchen with the fewest equipment.
Larger homes may tend to store rainwater for general use, so under deck rainwater tanks are ideal because of their larger capacities and space-saving qualities, which is why they are becoming more popular for suburban and urban areas.
For commercial establishments like restaurants and cafes that require larger volumes of water due to the nature of their business, galvanised or stainless steel tanks can store rainwater that could be safe for food preparation—provided the right filtering and treating equipment are installed along with the rainwater tank system.
Rainwater is a viable, renewable water source in times of droughts or shortages. Although stored rainwater may not be always safe to drink or use for food preparation, this water is safe for general use. Consult with a highly trusted rainwater tank supplier so you can find solutions to your needs!