He married twice. He married Hedwig Mackhohm in Duchy Holstein, November 21, 1727. He married Engel Kahl in Lütjenburg, Duchy Holstein, November 14, 1732. Engel was born in Wentorf, Duchy Holstein 1702. Engel died January 27, 1781 in Wentorf, Duchy Holstein, at 78 years of age.
Detlef Jep and Hedwig Mackhohm had the following child:
+ 5 iii. Claus Joachim Jep, was born January 11, 1736.
6 iv. Peter Hinrich Jep, was born in Wentorf, Duchy Holstein 1739.
+ 7 v. Catharina Jep, was born ca. 1746.
+ 8 vi. Mars Jep, was born ca. 1759.