Your tank could weigh over 2000 pounds (Depending on the model) when completely filled. Make sure it is on a level concrete floor with the entire bottom of the tank supported before you fill it. It's not necessary, but if you prefer a barrier between the tank and the floor, we recommend you use a flat piece of plastic, rubber, or plywood. Wooden pallets or structures are usually not strong enough to hold a full tank. Also keep in mind how you plan to drain it if you want to rotate your water in the future.
Once the spigots are installed and the tank is placed properly, you can begin filling your tank.
Take off or loosen the black top cap to let the air escape.
Fill the tank to just above the top spigot and wait for one hour.
Check to make sure that none of the fittings are leaking. If there are drips around a fitting, tighten it a quarter-turn and wait again. Repeat this step until there are no drips.
Fill your tank the rest of the way. Keep watch on it while it fills to make sure that it doesn't overflow.
Replace the top cap.