Pack cucumbers into 7 hot sterilized jars. Place 2 dill sprigs, 1/2 teaspoon mustard seeds, and 2 peppercorns into each jar.
Combine water, vinegar, and salt in a large stainless steel saucepan; bring to a boil. Pour over cucumbers, leaving 1/2-inch head space. Remove air bubbles. Cover with metal lids, and screw bands tight. Process in boiling water bath 15 minutes.