Does my carpet pad need replacing after being soaked?

Generally, yes, although, some newly developed restoration procedures may be able to salvage the cushion. Wet carpet cushion is very difficult to adequately dry quickly. 

If you are trying to salvage the carpet and pad, you need to dry it out, ideally, within 24 hrs! First of all, you probably need a professional water extracting company. A quick Google search for "water extraction company near me" should help you find a professional. The carpet may be OK. But, it may wrinkle, or the pad underneath may be ruined. Once you have the water dried up, we can come out to inspect and see what needs to be done if you are still within your one year warranty. Unfortunately, your warranty does not cover water damage, so there will be costs to you for any repairs or replacements needed. If the carpet is saturated with mud, sewage, or other contaminants, it is recommended to properly dispose of carpet and pad. Good luck!