How to monitor level and quality in rainwater storage tanks

Installing and maintaining a rainwater storage tank requires tracking the level and quality of the water. Today we’ll review solutions for doing so, from low-budget devices to high-end products, both portable and fixed.

After you finish reading, you can download our presentation, complete with additional details and graphics. In it, we’ll go over the main points of installation and configuration of these devices.

Table of content:

Why collect rainwater?

Let’s start with the positive impact energy-harvesting solutions have on the environment. Installing a rainwater storage tank reduces water consumption and reuses rainwater in activities such as watering gardens, flushing toilets, and washing clothes.

You’ll find these tanks in homes, farms, and industries, and all of the solutions presented here can apply to any of them. In today’s age, we must find alternative ways to provide energy and reduce resource consumption to avoid shortages.

According to a 2007 survey by the Australian Bureau of Statistics, people avoid rainwater tanks for three reasons. The first involves the cost. Although 47.5 percent of those surveyed had doubts about paying for this solution, a rainwater tank isn’t as complicated as you may think.

Others claimed a lack of time (28 percent) or room (15 percent). We can’t address those problems here. So let’s talk about what you can do to make rainwater storage cheaper!

What is a rainwater storage tank?

Before we go any further, let’s define the term “rainwater storage tank,” as you may know it by a different name. In North America, you might call it a rain barrel, and people in the UK call it a water butt.

A rainwater storage tank usually collects rain from rooftops via pipes, and they range in size from small barrels for home use up to giant reservoirs for farm or even industrial applications.

rainwater storage tank

What are common problems with rainwater storage tanks?

The types of problems you may have with these tanks can vary by location and setup, but let’s dive into two critical issues in this article: how to measure the level and how to maintain the quality of the water. You can handle both manually without any automation, but adding a few simple elements can help.

For instance, you can measure the pH of your water using portable or local devices. You’ll likely want to maintain a range between 6.5 and 8.5, but the pH can change depending on the material of the tank. For a simple application, a visual inspection should suffice to check for contamination.

What’s the best level measurement for rainwater storage tanks?

The right device for your application will depend on what the application itself needs as well as what you need and want. We divided the options into three sections.

First, we have the low-budget wireless level transmitters. These devices install and configure easily. However, you can’t integrate them into control systems or other types of controllers.

Second, you’ll see point level detectors. These devices can control pumps to turn on or off based on the level. If you don’t need a precise measurement, level point detectors work well for on/off control.

Finally, we have the high-end sensors, where you’ll get excellent accuracy and features, plus the ability to integrate them into your control system. If you want to see how to install and set up these devices, we prepared a downloadable guide with a simple explanation for each.

Wireless level measurement

These devices have different ways to measure and collect data. We’ll give a short description of each device here. To learn more, you can download our guide.

EcoMeter P

This level meter from E-Sensorix uses ultrasonic waves to measure. It comes with an integrated antenna and wireless display to receive your data remotely. And if you need a remote antenna, then you have that option as well.

image of Ecometer level sensor and monitoring system
Courtesy of E-Sensorix

The device can measure from half a meter to three meters in up to 19,999 liters and has a range of 150 meters. Its battery can last three years on a 15-second cycle, and the monitor uses power in the 150-to-240-volt range.

The EcoMeter P has different designs and materials available and comes with a threaded connection as standard. You can read our product review for more details.


The SenZ2 packs a lot of tech in its small blue box. It works with GSM, NB-IoT, or LoRa networks using a single global SIM chip. Also, it has a range from 250 to 5000 millimeters in liquids and solids.

image of  SenZ2 WLR05-2G/001 level transmitter
Courtesy of SenZ2

The SenZ2’s battery can last between one and 10 years, and it can send 96 measurements and 24 messages a day. Best of all, you can set it up using a cloud platform on your phone or laptop.

It has four installation options, including measuring through the lid if your lid is plastic. You can learn more from our definitive guide, including how to install and configure the SenZ2.

rainwater storage tank

The Ecofrog, another ultrasonic, uses WiFi to communicate. It can measure from half a meter to three meters and has a battery that can last 10 years with the right configuration.

image of Ecofrog from E-Sensorix
Courtesy of E-Sensorix

Speaking of configuration, the Ecofrog ships pre-configured, so you’ll need to give the vendor your specs when you order. You’ll need a threaded connection to install it, too.

It measures only liquids, but you can pull your data from a web app on your phone or laptop.

Point level measurement

Level switches give you a budget-friendly way to control your levels. A switch can detect low and high levels, with a relay output to turn the pump on or off. You can also have an LED or siren to signal low and high levels.

Liquipoint T FTW31

The Liquipoint T FTW31 can detect up to five points. It works in conductive liquids and measures from 0.1 to four meters. Plus, you can use its output to turn your pump on and off. It costs a little more than other choices but offers solid, long-lasting reliability.

In our guide, we’ll teach you how to install this device.

Liquipoint T FTW32

The Liquipoint T FTW32 has a bit more range, measuring from 0.25 to 15 meters. It can also control your process using a relay and detect the level of conductive liquids at five points.

As for installation, it should set up easily in your rainwater storage tank with thread connections.

High-end level solutions

If you want a precise device with fancier features than the previous entries, then here you go. These two devices provide good cost benefits, simple configuration, and high accuracy.


The Micropilot FMR10 has uses the time-of-flight concept to measure up to eight meters. You can configure it using a tablet or smartphone through the SmartBlue App for iOS and Android.

It doesn’t come with a display, but you can install a universal display. You can use the SmartBlue App to check your data as well.


The LST300 from ABB, an ultrasonic transmitter, works well in open channels and is easy to install and configure. It has a range of up to 10 meters and works from -40 to 85 degrees Celsius. This sensor is also loop-powered, meaning you get signal and power from the same pair of wires.

It has an accuracy of  +-2 mm or 0.2 percent of full span. You can configure it using the local display or HART communication, and you can add a remote display using HART or analog.

How do you monitor and maintain water quality in a rainwater storage tank?

As mentioned above, you can track your pH to maintain the quality of your rainwater. While you can use other methods, such as microbial analysis, they can complicate your setup more than pH.

Why do you need to measure pH in a rainwater storage tank?

The minerals found in water give it taste and health benefits, and they influence pH. If you have a pH value below than 7 you have acidic water, and above 7 you get alkaline water. Either could cause problems.

For drinkable water, you must remember that your body has a natural pH of 7.4. If you drink water without the proper minerals, you can put your own pH out of balance.

These two pH devices can help you monitor and maintain your water quality.

TX100 pH/ORP

This transmitter can pair with many pH sensors on the market. It has a local display where you can see pH and temperature. You can mount it on a DIN rail, pipe, panel, or wall. It also has a simple calibration process and maintenance alerts.

Portavo 902 pH

For a portable solution, the Portavo 902 pH could suit you. This device can work for more than 1000 hours using four AA batteries. It has a good user interface and display, too. You can connect analog pH sensors or even Memosens sensors to it.

The definitive guide on monitoring level and quality in rainwater storage tanks

If you want to learn more, then download our definitive guide on how to monitor level and quality in rainwater storage tanks. This guide can teach you about energy harvesting, rainwater storage tanks, and installation of the devices mentioned in this article.

rainwater storage tank

Recommended articles