Product Description

Need serious water storage without the headaches of piecing it all together? The RainFlo 3400-IG is a professional-class, high-capacity in-ground rainwater harvesting system built for large-scale use and built to make your life easier.

Whether you're managing a commercial site, agricultural property, or large estate, this system gives you everything in one box , no sourcing parts, no engineering stress, no wasting days trying to get components to work together.
Every component has been carefully selected and perfectly matched for optimal operation, so you get seamless performance from day one.

You’re not just saving water, you're slashing operational costs, protecting your land from runoff, and ensuring your property has a reliable, off-grid water source that keeps you running even during restrictions or shortages.

With dual-tank storage and durable, field-tested construction, the RainFlo 3400-IG delivers serious capacity, long-term durability, and simple installation all while helping you make a smarter, more sustainable impact on your property and the environment.

The RainFlo 3400-IG is a professional-class complete in-ground 3,400 gallon rainwater harvesting system. Every component has been carefully selected and perfectly matched for optimal performance.

The Tank Guaranteed Not to Collapse When Empty*
* When installed in compliance with manufacturer's installation instructions

15 Year manufacturer's warranty

Features

• Graf 1700 Gallon Carat Tank – Primary underground cistern with pedestrian-rated manway, 14" telescopic riser, and childproof PE lid. Can be left empty without risk of collapse.

• Graf 1700 Gallon Carat Extension Tank – Additional sealed underground tank used to expand total system capacity without requiring a second access point.

• Graf Optimax Pro Internal Filter Package – Self-cleaning cascade filter system with calming inlet, overflow siphon, and fittings. Supports roof areas up to 3,750 sq. ft.

• Graf Opticlean® Spray Head – Delivers 16 powerful water jets to clean the Optimax filter cartridge, minimizing manual maintenance.

• RainFlo 1.25 HP Submersible Pump – 3-stage 230V pump delivering up to 24 GPM and 78 PSI for high-demand water delivery.

• RainFlo 230V Automatic Pump Controller – Multi-function controller that automates and protects pump operation.

• RainFlo 1.25" Floating Extractor – Draws water from 4" below the surface for cleaner, oxygen-rich water.

• RainFlo Pump Connection Kit – Includes MPT to hose barb adapter and marine-grade stainless steel hose clamp for quick, secure installation.

• Bulkhead Fittings – Includes (2) 2" fittings to connect both tanks, (1) 2" vent fitting, and (1) 1.25" fitting for pump discharge.

• 2" Vent Cap – Allows proper air exchange between tanks during filling and draining.

• Multi-Tite Sealing Gaskets – (2) 2" and (2) 4" gaskets for watertight pipe penetrations and air balancing lines.

System Includes:

	The Graf 1700 Gallon Carat Tank - Graf Carat-S 1700 Gallon Underground Cistern with Pedestrian Manway, 14" Height Telescopic Riser and Childproof PE Lid. Unlike most cisterns, the Carat can be left empty without the risk of collapsing.
	The Graf 1700 Gallon Carat Extension Tank - Graf Carat-S 1700 Gallon Underground Cistern Extension. The tank is completely sealed without an access opening. Used to expand your tank capacity more cost effectively
	The Graf Optimax Pro Internal Filter Package - Internal self-cleaning cascade filter package. Includes filter, downpipe attachments, calming inlet, overflow siphon and Spannfix sleeve. Suitable for roof areas up to 3,750 sq. ft.
	The Graf Opticlean® Spray head - The Opticlean® cleaning unit provides 16 intense water jets for cleaning the Optimax® filter cartridge, keeping routine maintenance intervals to a minimum.
	The RainFlo 1.25 Horsepower Submersible Pump - Heavy-duty, high performance 230V/60Hz 1.25 horsepower 3-stage submersible pump with 1.25" threaded inlet to easily accept a floating extractor. Produces up to 24 GPM and up to 78 PSI.
	The RainFlo 230V Automatic Pump Controller - Provides automatic multi-function control for your water pump.
	The RainFlo 1.25" Floating Extractor - The floating extractor consists of an air-filled ball which suspends the floating inlet filter 4" below the water's surface where the cleanest and most oxygenated water resides.
	The RainFlo Pump Connection Kit with MPT to hose barb adapter and marine-grade stainless steel hose clamp to connect the RainFlo pump to the floating extractor.
	Bulkhead Fittings - (2) 2" bulkhead fittings are supplied for connecting the two tanks together at the bottom so that they act as one large tank. (1) 2" bulkhead fitting is supplied for connecting the vent cap to allow air into the tank. (1) 1.25" bulkhead fitting is supplied for the penetration required to run your pump discharge line out to your irrigation system or home.
	2" Vent Cap - Allows air to enter and escape from the extension tank to allow water to fill the tank.
	Multi-Tite sealing gaskets - (2) 2" Multi-Tite gaskets used to produce a watertight seal around the upper air balancing lines. (2) 4" Multi-Tite piping gaskets used to create a watertight seal with any penetrating piping.