pH of Rainwater? Causes And Its Impact (2023)

Before you use your collected rainwater for various purposes, you’ll need to know something about your rainwater pH. As we know pH stands for potential of hydrogen and it determines whether your collected rainwater is acidic, alkaline or neutral.

pH of your tapwater is in between 6.5–8.5 which you use it for drinking and other purposes. pH is measured in the number between 0-14, with 7.0 being considered neutral and any number below and above are considered as acidic and alkaline respectively.

pH of rainwater is essential because it determines whether you can use your collected rainwater for gardening, dishwashing, swimming pool and for drinking purposes or not. Many homes which are near to industrial areas may have suffer from acid rain and because of this their usability of collected rainwater is limited.

Check your rainwater pH before use

By considering pH of rainwater as a major parameter you can easily enhance the treatment capabilities of your rainwater harvesting system. Maintaining pH level of your collected rainwater between 6.5 and 8.0 would be great because acidic and alkaline properties of water have adverse effect on our daily use. An acidic water is corrosive in nature and can’t be used for gardening and consumption purposes.

Gardening: Most plants grow in the soils with pH between 6.0 and 7.0, before watering your plant you must check its pH level, because it may be harmful for your plants. Adjusting the pH after filtration unit is mandatory for plants.

Dishwashing: pH of dishwasher soap are generally above 7.0, because it require slightly alkaline solution to get rid of oil and grease from your leftover food. The closer your dish soap and water solution pH gets to 7, more lesser its cleaning effectiveness would be. In most homes tap water is used for cleaning the dishes and it is maintained at 6.5-8.0. But if you want to use rainwater for kitchen purpose you should take care of this alkalinity problem.

Sinks, washroom and swimming pools: If you are using your rainwater for sinks utilities and bathing purposes you should be careful because your skin is sensitive to pH. Your skins are healthy in acidic environment as acidity kills many microbes, bacteria and coliform which are attached to our body and get washed out when we take bath or clean our hands.

Pets washing: Be careful if you are washing your dog or cat with rainwater. In a study it was found that most of the pet’s skin are alkaline, making it perfect environment for bacteria to grow. If pH of water is disrupted it can cause skin infection to pets.

Car Washing: If you are thinking that car can be washed through any water then you are wrong! Washing your car might seem like relatively straightforward way but it’s not. In order to clean your vehicle high and low pH presoak are used, High pH presoak remove organic matters such as bugs, grease, bird poops and all living microbes from your vehicle while low pH presoak removes non-living materials like silt, dirt, clay and sands from the surface. So, using rainwater in place of tap water would be a great choice for car washing but you should also consider its pH level.

Washing Machine: If you want to save electricity and detergent cost you might have to use water that has pH close to 7. In a study it was found that when pH of water is above or below 7, more surfactant, cleaning products and washing time are consumed. So, maintaining pH of rainwater is also a major concern while washing your clothes.

Drinking purposes: As per EPA guidelines pH of drinking water should be between 6.5 and 8.5. Water that has pH range outside of the recommendation can be harmful for us. Alkaline water not necessarily unsafe but drinking alkaline water can have unpleasant smell or taste on the other hand acidic water that has pH less than 6.5 is more likely to be contaminated with pollutants and it is unsafe for drinking. So, pH of rainwater must be balanced before human consumption.

Piping System: Fluctuation in water’s pH can cause water to be corrosive in nature and with prolonged time it can cause scale build up on fixtures and inside pipes. Over time, your pipes of rainwater harvesting system can lose pressure and your water carrying appliances work on lower efficiency. To avoid such things pH meter can be installed at the outlet of storage tank, which enhances your component of rainwater harvesting system.

Tap water coming to your home from municipal water supplies generally maintain their pH level between 6.0 and 8.0, so there is no requirement to test your home tap water. But if you notice that your sink utilities faucet, shower and pipes are getting rusted or you see any white, blue and green color on its surface, you might have to take some action.

The discoloration you see on your water carrying appliances is a sign of fluctuation of pH in your water. There are lots of pH test kits are available in the market from simple pH test strips paper to electronic devices. These are the steps you should follow to check your pH of tap water/rainwater with simple test strip paper.

Step 1: Take a glass and fill it with the water you want to check. Dip the pH test strip for about 3-5 seconds.

Step 2: Take out the strip from water and wait for next 10 seconds.

Step 3: You notice that the color of the strip changes, if the strip color become red your water is acidic and if the color become blue it is more likely to be alkaline. If you notice that the color is green then congratulation, your water is close to 7.0

Step 4: If you see some other color other than mentioned above then use the indicator scale of different colors on the test kit provided to determine the pH.