First figure out how much water all the pigs need: 8 pigs * 3 gallons/pig = <<8*3=24>>24 gallons
Then figure out how much water one horse needs by multiplying a pig's needs by 2: 3 gallons * 2 = <<3*2=6>>6 gallons
Now find how much water all the horses need: 10 horses * 6 gallons/horse = <<10*6=60>>60 gallons
Finally, add up all the animals' water needs: 24 gallons + 60 gallons + 30 gallons = <<24+60+30=114>>114 gallons
#### 114