Water and electronics generally do not make happy bedfellows. Unlike recent models of iPhone, your iPad is not designed to be water resistant. While the iPad may survive being splashed with water if immediately dried, it will almost certainly suffer irreparable damage if it is allowed to get wet, or is submerged for any length of time.
If the worst should happen, speed is essential. If the iPad gets wet, it should be immediately dried with an absorbent towel - then set aside in a warm, dry location to thoroughly dry. The iPad should be turned-off - and no attempt made to turn-on, use, or charge the iPad until you are absolutely certain that the iPad has fully dried out. Pay particular attention to the charging port.
While you can safely use Silica Gell sachets to aid the drying process, never use rice to aid the drying process; unavoidable dust from the rice will cause more damage and encourage mould growth.
While the iPad is unlikely to be repairable, if you need the iPad to be assessed and seek assurance that the iPhone is okay, a visit to the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) will provide opportunity for the technicians to test and assess the iPad and iPhone for damage:
Genius Bar Reservation and Apple Support Options - Apple
For practical purposes, in lieu of repairing and returning an iPad, Apple usually exchange a qualifying iPad for a renewed/refurbished iPad of the same model and specification. The cost of the exchange is the same as would otherwise be charged for repair. Unless you have benefit of an active AppleCare plan, an out-of-warranty repair will be expensive but somewhat less than the cost of purchasing a new iPad.
As for out-of-warranty repair costs, Apple offers a fixed-price price repair. You can verify eligibility and cost for your region/country here:
iPad Repair & Service - Apple Support
If you have an active AppleCare+ plan, the cost of repair is reduced to a small excess/deductible fee.