What are the Advantages and Disadvantages of Rainwater Harvesting?

A breakdown of the various advantages and disadvantages of rainwater harvesting.

rainy roof

Rainwater harvesting can be a great way of avoiding rising water costs and utilising the resources we have all around us. However, there is always at least a little bit of cloud to every silver lining and the balance of the positives and negatives should be considered carefully before settling on investing in any such system.

So, what are the advantages and disadvantages of rainwater harvesting?


1. Low-cost Maintenance

Once the system is all up and running, you really don’t need to invest much money in keeping it running. If you intend only to use the collected water for non-drinking purposes, you don’t even need to purify the water.

2. Lower Water Bills

Collecting your own water means spending less on the water companies’ water. Water can be used to flush toilets, wash clothes and dishes, and to water gardens. On a bigger scale, rainwater harvesting can lead to major savings for households or small businesses.

3. Great for Irrigation

Rainwater is not subjected to any chemicals found in ground water and therefore is ideal for irrigation as well as for watering plants in the garden.

4. Reduces Ground Water Demand

As our population increases, so does the demand for water. In many areas, ground water is extracted to keep up with demand and this has lead to low levels of ground water being left over.

5. Reduces Soil Erosion and Floods

By keeping rainwater from reaching the ground, it is possible to prevent flooding if carried out on a large-enough scale. Rainwater harvesting also reduces soil erosion and keeps surface water from being contaminated with pesticides and fertilizers from rainwater run-off.

6. Multi-Purpose

Rainwater can be used for all sorts of things from flushing toilets, to washing clothes, cars, and dishes, to keeping the garden freshly watered.


1. Unreliable rainfall

Isn’t it just always the case that right when you need something it suddenly isn’t there? Rain is no different, and it can’t be relied upon to fall exactly when it’s needed. However, here in the UK we shouldn’t worry too much. You are unlikely to spend very long periods of time without plenty of rainwater to use.

2. Starting costs

Installing a rainwater harvesting system can be costly, with systems ranging from the low hundreds to the low thousands in cost. Similarly to solar panels, costs can be recovered in 10-15 years depending upon the rainfall and the system’s sophistication.

3. High-energy Maintenance

Rainwater harvesting tanks will take a lot of looking after, and even if this doesn’t cost much in terms of money it can become a chore. Systems can be infiltrated by rodents, algae, and insects, and can become breeding grounds for all sorts of creatures if not properly maintained.

4. Chemical roof seepage

Some kinds of roof coverings will seep chemicals which will prove harmful to plant life if the water is used to sustain it.

5. Storage limits

You may find that you cannot store all of the water you would like to, and this could mean having to tailor your water usage to the capacity of the tank.

It’s up to you!

There is no right way of going about many things, and often there are cons to the pros. Overall, rainwater harvesting is beneficial to the environment and could be helpful to your bank account. Just remember to consider both the advantages and disadvantages of rainwater harvesting before you settle on a decision.

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