Rainwater Harvesting

ABC of Rainwater Management Solutions

I woke up under a gray sky. Today is going to be a rainy day. I come from a rainy country, Belgium. At my parents’ house we had a rainwater well I remember being cleaned out once a year. That well would collect the water from the rain. We’d take our showers and flush the toilet from water taken directly from the well.

I guess my parents saved a fortune on their water utility bills. With hindsight, I know they did what they could to save the planet too.

Raindrop water collector

In those days, – they built our home in the early seventies, – few private homes with some land had a water well. The idea was not to be self-sufficient. Rainwater already then was not suitable for household use. Now we have filters. But back in 1970 they would have been hard to find.

While I look out of my window watching the rain come down, I wonder. Could I have planned the water management of my hotel differently? When I started planning the MARCEL in Buenos Aires in 2011 water here was cheap. I once made the calculation: water in Buenos Aires anno 2011 was 21 times cheaper ( cost per cubic meter ) than in Brussels.

I pay per consumption but in Argentina their are thousands of households without a water meter. That in itself is problematic as they are not held responsible for their water consumption.

Water is a scarce commodity and it is essential to manage water sustainably.

If you have access to rainwater, here is the ABC of rainwater management solutions.

Is it legal to collect rainwater?

Before you start digging a well, installing pipes and converting your roof, you need to verify your actions are legal.

In the US

According to the US legislation, “Rainwater harvesting is commonly defined as the act of utilizing a system to collect and use rainwater for outdoor uses, plumbing, and, in some cases, consumption. Rainwater collection or rainwater catchment are other terms used to refer to this practice.”

Legislators must ensure water quality standards and public health concerns are met when considering rainwater harvesting legislation. For example, collected rainwater may be used for non-potable purposes (e.g., watering indoor or outdoor plants) but may be restricted for potable purposes (e.g., drinking water).

Within the Continental U.S. the majority of States actually allow, if not support, rainwater harvesting, not ban it’s use. But very local health/law codes should always be checked. Colorado is the only state with extensive law restrictions applying to rainwater harvesting, and even then, the action is not illegal and is due to water scarcity within the region and a sensitive environmental balance that is trying to be maintained for many reasons.

USA chart for rainwater collection

For a more precise state of regulation in the USA, read here.

In Flanders

the northern part of Belgium, where I originally come from, the collection of rainwater is not only allowed, it is even required by law.

Rainwater collection being a regional issue, the Flemish government has a preferred order of how to drain unpolluted rainwater:

  • Collection and reuse
  • Infiltrate on own property
  • Buffering. Possibly with delayed drainage in an adjacent canal or surface water
  • Discharge into the sewage system in the street or a watercourse.
  • Discharge into the mixed sewer system in the street
  • None of those options possible? Only then may you discharge rainwater into the public sewer system.

The Flemish legislation also provides clear rules for building & installing a rainwater well.

For single-family homes exceeding 40 square meters, the installation of a rainwater well of at least 5,000 liters is compulsory. When the house is fully covered by a green roof, or in case it is only partially covered, it is not required for the parts with a green roof.

In Argentina

Argentina as a country does NOT have a water management legislation. That does not surprise me as most of the lawmaker’s attention is focused on political corruption and how to jail your political opponent.

In February 2020 Martín Sereno, a provincial deputy for Misiones ( home of the world-famous Iguazu Waterfalls ) proposed a bill to create the Provincial Program for Rainwater Harvests, an initiative that seeks new buildings to implement rainwater collection mechanisms or for existing buildings to add one.

In a province that is so dependent on water for domestic, commercial, industrial and public works AND for tourism, promoting the reuse and efficient management of water resources is of life importance.

It is sadly surprising to see that few or rather none of the other provinces in Argentina have a water management regulation in place.

How can we store & safe rainwater?

Collecting & Filtering Rainwater in a Barrel

In this centuries-old water collection system, the rain travels from the roof of the house to the barrel, using the traditional system of gutters or drainage pipes. An effective method of collecting rainwater.

water filtering in a barrelIf you have easy and cheap access to used barrels ( when you live in a wine making region ), you might look into this option.

You can select the barrels to use based on the depth, depending on the quantity of water you plan to use.

Rainwater, in addition to being better for washing clothes, is also better for watering and gardening fields. Water without chlorine or other types of salts added bring vitality to your plants.

By simply installing a tap in the barrel, you can connect a hose making the watering of your garden easier.

Modern Solutions

If you were thinking right now, ‘what an odd idea to think I’d want something clumsy like an oat barrel in my garden”, then the following modern ecodesigns will prove you wrong.


The award-wining design, based on the graduation work of Dutch designer Bas van der Veer, has been completely redesigned from the ground up with some major technical improvements, new surface finishes and contemporary colors.



Whilst I still have found one for sale on fonq.be, it is no longer listed on the web page of its manufacturer ELHO.com. When they get back to me, I will keep all of you guys posted.





Freeflush in the UK offers a wide range of simple rainwater harvesting solutions. Their products and services cover technologies for

Freeflush rainwater harvesting
  • Rainwater harvesting Prestige Wall by Freeflush
  • Stormwater
  • Waste Water
  • Irrigation
  • Drinking Water
  • Other Water Saving technologies

The rainwater harvesting butts range in color, size and style, so there is one for every budget and taste. They come in classic to go with a Mediterranean surrounding, modern, but none will be as stylish as the Elho’s Raindrop.

Goplus portable rain barrel


If you do not fancy a sexy rainwater harvesting solution,

Goplus Portable Rain Barrel

Water Collector Collapsible Tank

w/Spigot Water Storage Container (100 Gallon)

available on Amazon in the US

Courses on Rainwater Harvesting by ARCSA

Corona has marked the arrival of online classes in every field.

You can even take classes the ARCSA professional rainwater harvesting class online.

How can we purify rainwater for consumption?

When rainwater is going to be used for human consumption, the water must be tanked and treated so you don’t get bacterial and mold growth or provide a breeding ground for insects. This is food for my next article here.

Lots to read out there

There are plenty of books where you can learn how to harvest rainwater, how to treat it and how to best install the tools.

Here are some as an example.

Designing Rainwater Harvesting System

Water conservation is one of the most effective sustainable design practices, yet few professionals know how to collect and use rainwater effectively. Rainwater Harvesting the first comprehensive book on designing rainwater harvesting systems. It provides practical guidelines for developing a rainwater harvesting strategy, taking into account climate, public policies, environmental impact, and end uses. Case studies are included throughout. Rainwater Harvesting is a valuable reference for architects, landscape architects, and site engineers.

The Water-Wise Home






Save the earth’s most precious resource while also saving yourself money. Laura Allen provides expert strategies for using water smartly and efficiently while fulfilling all of your home and garden needs. Learn how to create a water-wise landscape, reuse greywater, harvest rainwater, and even set up a waterless composting toilet. Offering proven techniques in clear and accessible language, The Water-Wise Home makes it easy to help the environment and lower your household operating costs through conserving water.

3 thoughts on “ABC of Rainwater Management Solutions”

  1. I liked reading your article on rain water harvesting a lot and it did make me think that the law should be that we need to be doing everything that we can for the environment. 

    I must admit my limitations are the use of water butts mainly for the garden but I suppose that it is a start and after reading your article I will be looking further into how I can help further. 

    You have provided so much information and believe that by you sharing we can hopefully use where it is needed most and helps others.

    Thank you so much

    • Hi Imelda,  Love the fact that you like my article. It is my dream to one day build or renovate a small house and do it in a 100% eco friendly way. There is more useful info to be found on my website. I hope you find the time to explore.


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