What are Wet and Dry Rainwater Harvesting Systems?

Wet systems and dry systems refer to methods of piping your roof water to your rainwater tank.

• In a Wet System, the pipes from your gutters go down and underground then up into your tank. Because they travel underground and sit below the level of your tank inlets, these pipes remain full of water even during periods of time without rainfall.
• In a Dry System, the pipes from your gutters run directly into the top of your tank. Because the pipes are above your inlets, they are able to fully empty into your tank and stay dry after it rains.

So when would you use a wet system and when would you use a dry system?

Wet Systems are great when you want to place your water tank away from your roof. Rather than have long, unsightly pipework reaching through the sky to the tank, you can neatly hide the piping under the ground.

Unfortunately, because wet systems hold water in the pipes during rain events, they can be prone to mosquito infestations and anaerobic fermentation. Because of this, it’s important to periodically empty your pipes to remove old waters. One way is with an In-Ground First Flush Water Diverter.

Wet System installation can also be more expensive as you need to dig a trench to bury your plumbing.

Dry Systems are the ideal set up when your tank is located next to your roof.

Dry system installation is also generally quicker, easier and cheaper than a wet system as you don’t need as many pipes and you don’t need to dig.

And because the pipes automatically dry out between rain events there is less to maintain. So, as long as your water tank is not too far from your roof, the installation can still look neat.

Which system you choose will depend on your property layout, your personal preferences and your budget. A wet system is neat solution while a dry system is an easy solution.

If you are shopping for components for your rainwater harvesting system, check out our range of rain harvesting accessories.