Decanter of Endless Water is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

You have no maximum hand size. : Add one mana of any color.

Complete guide

Decanter of Endless Water is a versatile artifact that provides both mana ramp and a powerful passive utility for players who love drawing cards. It serves as a reliable mana rock while ensuring you never have to discard your resources at the end of your turn.

Continuous Hand Size Expansion

The first ability of Decanter of Endless Water is a static effect that eliminates your maximum hand size. As long as this artifact is on the battlefield, you are exempt from the rule that requires players to discard down to seven cards during their cleanup step. This effect applies immediately and does not require any mana to activate.

Mana Production and Color Fixing

By tapping Decanter of Endless Water, you can add one mana of any color to your mana pool. This is a mana ability, meaning it does not use the stack and cannot be responded to. It is an excellent tool for fixing your mana base in multi-color decks while simultaneously accelerating your game plan.

The Cleanup Step Process

Under normal circumstances, the cleanup step involves two main actions: discarding down to your maximum hand size and removing all damage from permanents. With this artifact in play, you simply skip the discard portion of that step. If Decanter of Endless Water leaves the battlefield during your turn, you will be subject to your normal hand size limit once you reach your next cleanup step.

When to Deploy It

This card is best played early to accelerate your mana or right before you resolve a large draw spell. Because it provides any color of mana, it helps cast high-cost spells that have strict color requirements, all while protecting the cards you just drew from being discarded.

Interaction examples

Managing Large Hand Sizes

If you have twelve cards in your hand at the end of your postcombat main phase, you move to the beginning of your ending phase. During the cleanup step, the game checks your hand size. Because Decanter of Endless Water is on the battlefield, your maximum hand size is non-existent, and you proceed to the next turn without discarding any cards.

Fixing Your Colors

Suppose you are playing a three-color deck and only have lands that produce two of those colors. You can tap Decanter of Endless Water to produce the third color, allowing you to cast spells you otherwise couldn't. This mana can be used during your main phase or even on an opponent's turn to cast instant-speed spells.

Guide written with AI from the official text and rulings. Official English text prevails.