29 May 2025

Is rain harvesting worth it?

A 2025 Perspective for New Zealand, the US, and Australia

Rainwater harvesting has long been a practical solution in New Zealand, but as water scarcity, climate change, and rising utility costs become global concerns, interest in rainwater harvesting is surging in the United States and Australia as well.

Around the world, it is only in times when water restrictions are in place that we take a step back and consider what it means when we take that extra-long shower or leave the sprinkler on in the garden. We get so used to turning the tap and having ready access to clean, fresh water.

When we are told that we can’t use it as freely as we have become used to or that we need to reduce the time we spend in the shower, for example, it’s only then that we start to think about the repercussions of our water use and the impact on the environment around us.

Rainwater harvesting in New Zealand and around the world is not something new. Many houses, both old and new, still rely on harvesting rainwater in tanks as their only supply of water. Other houses have adopted a hybrid model whereby the property will be connected to the mains, however, they use harvested rainwater as and when they can, depending on how much they are able to collect.

During times of drought and water restrictions, more people start to think about the benefits of rainwater harvesting and ask – Is it worth it? The question of whether rainwater harvesting is worth it is usually twofold:

  • What will be the impact on the environment and waste?
  • What is the potential return on investment of installing a rainwater tank at home?

This updated guide explores the environmental and economic benefits, addresses common concerns, and provides market-specific insights for New Zealand, the US, and Australia in 2025.

What Is Rainwater Harvesting?

Rainwater harvesting is the process of collecting and storing rainwater from rooftops or other surfaces for later use. Typical applications include garden irrigation, toilet flushing, laundry, and, with proper treatment, even drinking water. Systems range from simple rain barrels to advanced, cloud-connected tank monitoring solutions.

The Benefits of Harvesting Rainwater

The benefits of harvesting rainwater are twofold: environmental and economic.

From an environmental perspective, rainwater harvesting is a simple and sustainable way to protect our planet’s natural resources and delicate ecosystems.

When we use harvested water, we conserve groundwater, save energy, limit the damaging effects of stormwater runoff, and bring out the best in our lawns and gardens.

Environmental benefits of harvesting rainwater

Conserves groundwater

As the global climate changes and drought conditions become more prevalent, including here in New Zealand, some urban areas, farms, and industrial sites are turning to groundwater extraction to meet the growing demand.

This type of water sourcing can be destructive. Groundwater aquifers can be tainted with fertilisers, pesticides and other chemicals and the more groundwater we use, the more concentrated these pollutants become, decreasing the overall quality of the water.

Harvesting rainwater means less reliance on groundwater supplies, giving aquifers the opportunity to refill.

Reduces energy consumption

The energy required to keep our mains water flowing is significant. That water has to be treated and piped, and this places demands on water treatment plants, pumping stations and the machines that are used to repair the sewer and water lines.

Whilst these resources are well spent on ensuring we all have access to clean water in our homes. Potable (water suitable for drinking, washing etc) does not need to be used for flushing the toilet, washing your clothes or watering the garden.

By harvesting rainwater for these non-potable uses, we can help to reduce the strain on the mains system and reduce the amount of energy needed to keep powering our mains water supply.

Reduce stormwater runoff

Stormwater runoff can lead to a wide range of issues. Due to growing urbanisation, stormwater runoff is becoming a much bigger problem, with water that would previously have been absorbed into the ground now having nowhere to go, thanks to the large amount of concrete and asphalt in and around our major cities.

When that rainwater remains on the surface, it sweeps sediment, metals, pesticides and fertilisers into the catchment areas, which can pollute lakes and rivers, cause illness for humans and livestock and lead to the decline of some aquatic species.

Low-lying areas can also be subject to flooding if stormwater has nowhere to go, causing further issues, including subsidence and erosion.

Harvesting rainwater helps to reduce the strain on stormwater systems and prevent debris from entering the watershed.

Economic benefits of harvesting rainwater

Reduce water bills

The most obvious benefit of harvesting rainwater is the money you will save on your water bills each month. Depending on the size of the rainwater tank that you install, you can use the water you harvest for a variety of tasks, from watering the garden to providing the majority of water you use for drinking, showering and cooking.

Even a simple rainwater barrel can save you money if that water can be used to water your garden instead of relying on your mains water supply. This is especially true in years where water restrictions are in place, allowing you to water your garden all year round.

Halt rising water costs

Whilst you might see a direct benefit in terms of cost savings by utilising the rainwater that you harvest from your property, installing a rainwater tank can have wider economic benefits.

By reducing the strain on the mains water supply, you can help to lower the cost of pumping and treating that water. As rainwater tanks become part of the water harvesting ecosystem, the overall infrastructure cost for water management will also go down.

The Cons of Harvesting Rainwater

Whilst there are many benefits of harvesting rainwater, there are some cons that need to be considered.

Cost

The upfront cost of installing a rainwater tank can be prohibitive, especially for commercial properties. Domestically, large rainwater tanks that are used as an alternative to mains water can also be expensive to install.

When you are considering whether rainwater harvesting is worth it, it is good to understand the potential return on investment of your tank. A simple rainwater barrel, for example, might cost you as little as $100, and you might see a return on investment in a couple of years, depending on how you use the water around the garden and outdoors.

A large 30,000-litre tank will cost you in the region of $3,500 and up, and this investment can take longer to see a return. Water bills, on average, are between $20-$40 per month, meaning it could take up to 10 years to see a return on your tank (and that’s before you factor in the cost of installation that can add another couple of thousand dollars to the total installation cost). Still, if you are planning on living in a property for that length of time and beyond, this could still represent a good investment in the long term.

Maintenance

Whilst a lot of rainwater tanks are fairly low maintenance, there is still work that needs to be carried out regularly to ensure the quality of the water you are collecting – an issue you don’t have to worry about with mains water. Keeping gutters clean, ensuring there are no leaks and checking the quality of the water are all regular tasks that need to be carried out and can take time.

Unpredictable rains

Whilst it’s great having the ability to capture the rain that falls, especially during the wetter months in winter and autumn, unpredictable rains over the past decade mean that there is no guarantee that enough rain will fall to fill your tank to its full capacity.

With properties that rely on their rainwater tanks as the only supply of water, this can mean you incur further costs to top up the tank in drier years.

Storing your tank

If you want to maximise your rainwater harvesting, you will need a large tank. Storing that tank can be problematic. Whilst underground storage is ideal, retrospectively installing a tank underground can be extremely costly and disruptive, and so the majority of tanks installed at existing properties tend to be above ground, and these can not only require a lot of space, but they can also look unsightly.

Whilst water tank designs are improving, with a move towards slimline tanks that can be positioned against properties, they still require a decent amount of space, and it’s not always easy for properties to accommodate them.

The New Zealand Experience

In New Zealand, rainwater harvesting is both a tradition and a necessity, especially in rural areas and on properties not connected to municipal water supplies. With average daily water use in Auckland ranging from 140 to 170 litres per person, and recurring droughts putting pressure on reservoirs, many households have adopted rainwater tanks—from small 200-litre barrels to 30,000-litre underground tanks—to supplement or replace mains water.

Environmental Benefits:

  • Reduces pressure on groundwater and mains supply
  • Minimises stormwater runoff, decreasing pollution and urban flooding
  • Conserves energy otherwise used for water treatment and distribution

Economic Benefits:

  • Cuts monthly water bills
  • Reduces infrastructure costs for water management
  • Potential for return on investment, especially during periods of water restrictions

Challenges:

  • Upfront installation costs (can range from NZ$100 for a barrel to NZ$3,500+ for a large tank)
  • Ongoing maintenance (cleaning gutters, checking for leaks, water quality testing)
  • Space requirements for larger tanks, especially in urban settings

For more on the basics, see Collecting and using rainwater – a beginner’s guide and Should New Zealand be more proactive in collecting rainwater?.

Rainwater Harvesting in the United States

The US market for rainwater harvesting is expanding rapidly, driven by water scarcity, rising utility costs, and government incentives. In 2024, the North American rainwater harvesting market was valued at over USD 414 million and is expected to grow at a CAGR of 3.27% through 2033.

Key Drivers:

  • Severe and frequent droughts, especially in California, Arizona, and Texas
  • Water utility prices have surged by 25% over the past six years, with average monthly bills reaching $44.77 for typical households
  • Federal, state, and local incentives (e.g., Tucson’s grant and loan programs for rainwater harvesting installations)
  • Growing environmental awareness and corporate sustainability goals

Technological Advancements:

  • Modern filtration and purification systems make rainwater usable for a wider range of applications, including potable uses in some cases
  • Smart monitoring systems (like those offered by Smart Water) provide real-time data on tank levels, usage, and water quality, optimising efficiency and maintenance

Popular System Types:

  • Above-ground tanks and barrels are most common due to ease of installation and maintenance, making them ideal for both residential and commercial applications

Commercial Uptake:

  • Businesses (hotels, restaurants, factories) are major adopters, using harvested rainwater for landscaping, cooling, and cleaning to reduce costs and meet sustainability targets

The Australian Context

Australia, with its history of drought and water restrictions, has been a global leader in rainwater harvesting. Many states and territories have regulations or incentives supporting the installation of rainwater tanks, especially for new homes. In some regions, rainwater tanks are mandatory for new builds.

Benefits in Australia:

  • Reduces reliance on often-stressed municipal supplies
  • Helps manage stormwater and reduce urban flooding
  • Supports self-sufficiency in rural and peri-urban areas

Challenges:

  • Water quality concerns (especially in bushfire-prone areas)
  • Maintenance and mosquito control
  • Varying regulations between states and councils

Is Rainwater Harvesting Worth It in 2025?

Environmental Impact:

  • Reduces demand on municipal and groundwater sources
  • Mitigates urban flooding and pollution
  • Supports climate resilience in drought-prone regions

Economic Impact:

  • Direct savings on water bills—potentially hundreds of dollars per year, depending on local rates and system size
  • Increases property value and appeal, especially in areas with water restrictions
  • Government rebates and incentives can significantly reduce upfront costs

Technological Innovation:

  • Smart Water’s tank level indicators provide cloud connectivity, allowing users to monitor water levels, consumption, and pressure data from an app or LCD display—making rainwater harvesting easier and more efficient than ever.

Explore Smart Water’s range of rainwater harvesting products to find the right solution for your needs, whether you’re in New Zealand, the US, or Australia.

Common Concerns and Solutions

Concern Solution
Upfront cost Look for local rebates/incentives; start with a small system and scale up
Maintenance Use smart monitors, schedule regular checks, and install first-flush diverters
Space requirements Choose slimline or underground tanks; consult local suppliers for options
Water quality Install filtration and UV treatment for potable uses
Variable rainfall Use weather data and smart controls to optimise collection and usage

Conclusion

Rainwater harvesting is more relevant than ever in 2025. Whether you’re in New Zealand, the US, or Australia, the environmental and economic benefits are clear. With modern technology and growing government support, it’s easier and more cost-effective to get started. As water scarcity and climate change intensify, early adopters will reap the greatest rewards.

Ready to get started?

Browse Smart Water’s products or check out more resources in the Smart Water blog for expert advice, guides, and the latest industry news.

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Post first published 11 February 2022 and updated 29 May 2025