RINSE clean plastic containers and lids with boiling water. Dry thoroughly.
STEM and crush strawberries thoroughly, one layer at a time. Measure exactly 1 cup strawberries into large bowl. Cut rhubarb into 2-inch pieces. Finely chop or grind fruit. Measure exactly 1 cup rhubarb. Add to strawberries; mix well. Stir in sugar. Let stand 10 min., stirring occasionally.
MIX water and pectin in small saucepan. Bring to boil on high heat, stirring constantly. Boil and stir 1 min. Add to fruit mixture; stir 3 min. or until sugar is dissolved and no longer grainy. (A few sugar crystals may remain.)
FILL all containers immediately to within 1/2 inch of tops. Wipe off top edges of containers; immediately cover with lids. Let stand at room temperature 24 hours. Jam is now ready to use. Store in refrigerator up to 3 weeks or freeze extra containers up to 1 year. Thaw in refrigerator before using.