When it comes to Borderlands 4, few weapons combine sheer chaos and destructive beauty like the Waterfall Legendary grenade. This powerhouse doesn't just make explosions - it multiplies them. With the right build and a little bit of setup, the Waterfall can unleash infinite chain explosions that melt bosses and clear rooms faster than almost anything else in the game. Even better? You can farm the Waterfall early, making it one of the most powerful legendaries to grab at the start of your adventure.

In this guide, we'll cover everything you need to know - where to farm the Waterfall grenade, its unique effects, and how to trigger infinite explosions with the proper loadout.

How to Get the Waterfall Legendary Grenade in Borderlands 4

The Waterfall grenade drops from Bio-Bulkhead, a mid-game boss you encounter during the main story quest "One Fell Swoop." This mission sends you to the Order Facility, where Loctus - a volatile bio-chemical weapon - is being manufactured.

Once you reach the Order Facility, you'll face Bio-Bulkhead, a bulky mechanical monster coated in reactive armor. This fight introduces a unique mechanic: Loctus canisters.

Here's what you need to know about the encounter:

·Damage Immunity Phase: At the start of the fight, Bio-Bulkhead is completely immune to all attacks.

·Loctus Mechanic: You'll notice two Loctus dispensers in the arena. Grab the glowing canisters and throw them at the boss to strip its immunity.

·Armor Phases: After each phase, Bio-Bulkhead regains armor and goes immune again - meaning you'll need to keep using the Loctus canisters to progress.

The good news is that Bio-Bulkhead's loot pool includes the Waterfall grenade, alongside several other high-tier Legendaries. The drop rate isn't guaranteed, so you may need to repeat the encounter a few times. Fortunately, the fight is straightforward once you know the pattern - making it an excellent early-game farm.

Pro Tip: Equip a weapon with high single-target DPS, such as a Jakobs shotgun or Vladof SMG, to burn through Bio-Bulkhead's armor faster between Loctus phases.

Waterfall Legendary Grenade Unique Effect Explained

The Waterfall grenade's power lies in its namesake perk - "Waterfall." This effect causes an additional explosion each time the grenade deals damage.

Here's how it works in practice:

·When the grenade hits an enemy, it creates a primary explosion.

·That explosion then triggers a secondary blast, dealing bonus damage to all enemies in the radius.

·If those secondary explosions hit other enemies, they can also chain and trigger more explosions.

In short, it's an explosion that causes more explosions.

However, there's a catch. The secondary blasts only trigger if the grenade actually damages a target. If you throw it into an empty area or miss your shot, you'll just get the standard detonation with no chain effect.

What makes the Waterfall truly broken is the interaction between its chain explosions and area-of-effect scaling. With the right setup, you can make the secondary blasts big enough to chain infinitely between multiple enemies, creating a cascade of explosions that covers the entire battlefield.

How to Trigger Infinite Explosions with Waterfall

While the Waterfall grenade is powerful on its own, the infinite explosion loop comes from stacking radius and cooldown modifiers.

To make the most of it, you'll need three key components:

1. Expansive Perk on Waterfall - Increases blast radius. This is essential for creating overlapping explosion zones that can re-trigger the Waterfall effect.

2. Get Throwing Firmware (2-Set) - Reduces grenade cooldown and boosts throw rate. This ensures you can throw grenades fast enough to keep the chain going.

3. Airstrike Firmware (2-Set) - Further decreases cooldown time and adds minor splash benefits.

Once defeated, Bio-Bulkhead has a chance to drop the Waterfall grenade, along with other top-tier Borderlands 4 Items. The drop rate isn't guaranteed, so you might need to farm the boss multiple times - but thanks to the predictable mechanics, the fight is easy once you've mastered it.

Pro Tip: Equip a high-DPS weapon, such as a Jakobs shotgun or Vladof SMG, to quickly break through Bio-Bulkhead's armor between immunity phases. If you're low on resources, you can buy Borderlands 4 Items to strengthen your early-game setup and speed up the farm.

Waterfall Legendary Grenade Stats (Level 50 Example)

At Level 50, the Waterfall grenade features the following baseline stats:

·Cooldown: 11 seconds

·Damage: 6,716

·Radius: 488 cm

·Charges: 2

These numbers can vary depending on your character build, class mods, and bonus perks. The key is to focus on radius and cooldown reduction to maximize your explosive uptime.

If you're chasing god rolls, look for Waterfalls that drop with Expansive, Reactive, or Double-Trigger perks - all of which enhance either explosion size or frequency.

Why Waterfall Is One of the Best Early-Game Legendaries

Not only is the Waterfall grenade incredibly powerful, but it's also easy to farm early in the campaign, making it a must-have for any Vault Hunter. Its dual-charge system, short cooldown, and chain explosion mechanic make it a versatile tool for both mobbing and boss fights.

Here's why you should grab it as soon as possible:

·It clears rooms faster than most launchers.

·It synergizes perfectly with splash damage builds.

·It can delete bosses like they're made of paper.

·It scales well into endgame with the right modifiers.

Whether you prefer a gun-heavy build or a grenade spammer setup, the Waterfall will fit right in - and with its infinite explosion potential, it can carry you through most of the story with ease.

Final Thoughts

The Waterfall Legendary grenade in Borderlands 4 is the perfect mix of chaos, strategy, and pure destructive fun. Farming it from Bio-Bulkhead during the One Fell Swoop quest gives you an early-game advantage, while mastering its chain-explosion mechanic turns it into a late-game nuke.

With the right perks and firmware combinations, you can harness the full power of the Waterfall to create endless explosions - and there's nothing more satisfying in Borderlands than watching the entire battlefield erupt in cascading blasts.

If you're looking for one item that defines the word "Legendary," the Waterfall grenade is it. Grab it early, build around it, and let the explosions rain down.