The Pool is the third area and the stage of the third set of 10 levels in Adventure Mode. It is the backyard of the house in which the player lives, but unlike the front lawn (where the Day and Night stages take place) there are six rows instead of five. It might be this way because if there would be 1 water lane instead of 2 Garlics wouldn't work on Lily Pads. The middle two rows are the pool. Before the player buys Pool Cleaners, Lawn Mowers in the pool rows will kill only the first zombie that steps out of the water, and then splash into the pool. During the final wave in any pool level, Ducky Tube Zombies of most non-ZomBotany varieties (Normal, Conehead, Buckethead) will surface from a 4 by 2 rectangle at the far right of the pool with or without seaweed on their heads.thumb|300px|right|The music of the pool stage (called Watery Grave)
On the back side of the backyard, there are different types of ladders placed on the fence so the zombies can enter.
To beat any of the Pool levels, you need to use Lily Pad (unless you are going for the Pool's Closed achievement. The pool offers a lot of new, useful plants as well. Use Torchwood to help make your peas deal more damages. Use Tall-nut to stop zombies dead in their tracks. Use Tangle Kelp for the Snorkel Zombie. You can also put a Squash or a Wall-nut on a Lily Pad, also cheap. Use Jalapeno or Spikeweed to kill Zomboni. Dolphin Rider Zombies are very tedious but they can be killed with a Tangle Kelp or a Tall-nut. For more pool strategies, see here.
In the new iOS version, you will receive the Bacon at level 3-4 instead of the car keys because you already had the keys in 2-2 for the Bonus Games.
In any Survival Mode Pool levels in which they appear, Dancing Zombies will only be able to summon three Backup Dancers, as a fourth would be impossible to summon inside the Pool.
It is unknown how Vehicle Zombies are able to go up the ladders on the fence and onto your backyard.
In the Xbox Live Arcade version, there are no ladders leading to the Pool area, but instead, the zombies destroy the fence.
If a Ducky Tube Zombie is killed before it enters the pool, it will fall onto the surface of the pool just as a normal zombie will do on the lawn.