Use measuring tape and help from a friend to determine how long the space is that you’ll be using. This will help you to buy the right length of plastic for the slide. Note that the steeper the hill is, the more material you will need to extend past the hill, where sliders can slow down on a flat surface. Note that you will also need the slide to be positioned somewhere close enough for access to a garden hose.

Look or ask for plastic sheeting at a hardware store. You can use a heavy-duty contractor drop cloth, a long tarp, or other plastic sheeting available. It’s best to buy clear or light-colored plastic, as black will absorb more heat and become very hot in the sun.

Use sandbags or other heavy objects on the corners or sides of your plastic to help hold it in place, especially if it is windy. Remember to position your plastic so that there is a flat portion of the slide at the bottom of the hill you set up on. Otherwise, sliders will come to an abrupt and painful stop on the grass after building up speed from sliding on the hill.

Lay out pool noodles end to end on both long sides of your plastic, as well as the end if you want a stopper. The number of pool noodles will vary depending on your plastic length, but you can calculate based on a typical pool noodle length of 5 feet and a suggested 1 foot of space in between each noodle. Wrap the edges of the plastic all the way around the pool noodles so that the plastic touches itself again. Place 2 inch pieces of velcro where the plastic overlaps, at the ends and middle of each pool noodle, to keep them wrapped securely. Flip the whole slide over once all the pool noodles are secured in the plastic with velcro. This will create a smooth surface for sliding and prevent the velcro from coming undone. [2] X Research source

Cover each garden staple with a piece of duct tape to protect them from being stepped on or slid over. Use a bright color for the tape so that it’s highly visible. If you have enough material, fold over a small portion of your plastic once or twice at the top of the slide to double or quadruple it before staking it down. This will reinforce against tears at the beginning of the slide, which will get the most pull when sliders run and jump onto it.

Use a sprayer attachment on your hose, or a full sprinkler, to create a spray or mist of water so that it covers the whole slide. Use several sprinklers if you have them. You can also purchase a long sprinkler hose to run down the whole length of the slide to keep it wet. [3] X Research source

Add more of the dish soap/shampoo to the slide periodically to keep it slippery. [4] X Research source Keep the water from running down just the middle or one part of the slide by making sure there are no major creases or wrinkles in the plastic, or using multiple hoses/sprinklers.

Make sure to wear a bathing suit or clothing that will slide easily and that you don’t mind getting dirty or grass stained in the event that you slide off the plastic. It will help to get yourself wet or even lightly covered with the dish soap/shampoo before your first run on the slide for the best results.

There is also the chance of the plastic getting dirty, ripped, or even melted by environmental factors if left out between uses. If you used pool noodles, simple roll up the slide over the noodles at either edge, removing the stopper noodle if you have one, and fold it at the breaks in between noodles. At the end of the season, you can take all the noodles out to store the slide more compactly. You should be able to get several uses, even the whole summer, out of your homemade water slide with durable plastic and normal use. This can be a cost savings over store-bought water slides, which often have to be replaced after the first use.