Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a large mixing bowl, combine the sunflower seeds, pumpkin seeds, flaxseeds, sesame seeds, salt, garlic powder, onion powder, and dried herbs, if using.
Pour the water into the dry ingredients and mix until well combined. Let the mixture sit for about 10 minutes to allow the seeds to absorb the water and swell.
After resting, transfer the seed mixture onto the prepared baking sheet. Using a rolling pin, spread the mixture evenly across the baking sheet to about 1/8-inch thickness.
Use a sharp knife or pizza cutter to score the dough into cracker-sized pieces for easier breaking after baking.
Bake in the preheated oven for 25 minutes or until the edges are golden and the crackers are crisp.
Remove from the oven and allow to cool completely on the baking sheet. Break into pieces along the scored lines.
Store the seed crackers in an airtight container at room temperature for up to a week.