It’s usually best to add a pool slide when you initially install your pool. The reason for this is that most slides will require a water supply, so building this into your plan will avoid potential headaches of trying to add plumbing later. It also allows you to ensure that any slide you add fits with your pool design and deck configuration. If you do choose to delay the installation of a slide, it’s wise to make a full plan for it and have your installers add the necessary plumbing when they do the initial installation.