Greywater reuse reimagined
Compact. Simple. Smart.
PRE-ORDERS LAUNCHING SOON — SIGN UP TO JOIN THE WAITLIST​
FRESH WATER
GETS TO YOUR HOME
EACH LAUNDRY
USES AROUND 50L
GREYTANK
CATCHES, FILTERS & STORES
GREYWATER
FLUSH WITH REUSED WATER!
Compact.
Simple.
Affordable.
TURNING EVERYDAY ACTIONS INTO GLOBAL IMPACT
Calculate your potential water savings
No works needed
Connect greytank with a simple pipe
— no construction required.
During refurbishment
Easily integrate greytank while renovating.
In new builds
Plan greytank from day one for a seamless fit.
Need help? We support all three cases with planning and setup.
FAQs
What is GreyTank?​
Do I need to renovate my bathroom to install it?
Will it work in my home?
Does it filter the water?
Is it hygienic?
Who installs it?
What maintenance does it need?
Can I pre-order it?
greytank is a compact system that collects water from your washing machine and reuses it to flush your toilet.
It’s a smart way to stop wasting perfectly reusable water.
Nope! greytank is designed to be installed without construction in most homes. For new builds or refurbishments, you can prepare the space to make the system even more integrated.
Yes. greytank includes a filtration and disinfection system to ensure the reused water is safe for toilet use — no odors, no residues, just easy water reuse.
Absolutely. The reused water never comes into contact with drinking water. Plus, it's used only in the toilet, where water quality doesn’t need to be drinking-grade.
An average household can save up to 15,000 liters of drinking water per year — that’s the equivalent of what 20 people drink annually. Check our savings calculator!
Our team — or certified partners — take care of the installation. You don’t have to lift a finger (except to flush, of course).
Very little. We handle it for you. You’ll be notified if the filter ever needs changing or if anything needs a check-up.
Yes — or rather, very soon! Join the waitlist and be among the first to save water with style.
The team behind greytank
We’re architects, engineers, and entrepreneurs committed to a new water culture. Rooted in design, practicality, and common sense, we’re working to make water reuse at home as normal as recycling.​​​​​
Vidal Madrià
CEO​
Architect specialized in housing and sustainability​
Strategic advisors
We’re guided by professionals with deep experience in strategy, public policy, science, and communication:​​​​
Meritxell Guitart
Brand & impact​
Creative leader helping purpose-driven projects become strong brands​
Tristram Farnham
Technical development ​
Engineer with expertise in compact tank systems
Lluís Juncà
Public policy ​
Expert in innovation, regulation and institutional partnerships
Miquel Galimany
Prototyping & documentation
Engineer with a background in industrial laundry systems
Jordi Reverté
Strategy & finance ​
Experience in international business and the home water sector