You may swim in your hair extensions. The TemBond® is water resistant. Wearing a cap is recommended for long periods of time in the water (hours), a quick dip in the pool or even 30 minutes of laps is not going to harm your bonds at all.
Hot tubs and saunas are fine, just don't tug or pull at the extensions until you have returned to cooler temps.
To eliminate the water weight from adding stress to your own hair, and to prevent tangles, wear a loose pony or a braid when swimming.
Untangle wet extension hair with your fingers or carefully with a wide tooth comb while you dry your hair.
Please note that chlorine may dry out, and thus effect the texture of, your extension hair. (Careful care with washing and using the ManeMaxx® Extension Hair when you're going to be in chlorine pools and you should be able avoid the dry hair.) Also, too long periods of time in the water may cause bonds to shed. Once again, wearing a swimming cap will resolve this.
In high heat your bonds may soften. Don't pull at your extensions in 150+ degrees (like in a sauna for example.) Wait until you have returned to a cooler temperature until you brush, or tug, at your extensions.