Prepare jars and lids and canning bath according to safe canning practices.
In a large stainless steel stockpot, combine water, lime juice, tequila, Triple Sec and sugar. Bring to boil over medium heat, stirring constantly until sugar is completely dissolved.
Increase heat to medium-high and bring to full boil, stirring constantly. Stir in Pectin (and lime zest if using). Return to a full boil, stirring constantly for 1 minute. (Use a timer.).
Remove pot from heat and skim off any foam. Let jam cool in the pot for 5 minutes, stirring occasionally.
Ladle hot jam into hot jars, leaving a 1/4 inch headspace. Remove any air bubbles. Wipe jar rims and thread with a clean, damp paper towel. Center hot lids on jars and screw on bands until fingertip tight.
Place jars in canner, making sure they are covered by at least an inch of water. Cover and bring to a gentle boil, process 4-oz jars and 8-oz jars for 10 minutes; process 1-pint jars for 15 minutes.
Remove jars from canner and place on a cloth towel. Let cool for 24 hours, then check seals. Wash and dry jars and store in a cool, dry, dark location.