" Domestic gully Drains are a smaller scale of a storm gully Drain of which you would normally find them situated around the domestic property, if a domestic gully Drain becomes blocked it can normally be down to two common reasons as to why its has become a blocked domestic gully Drain, the most common reason why domestic gully Drains become blocked is because they act as a settling tank to some respect letting all the debris and rubbish Drain to the bottom of the domestic gully Drain to avoid it from flowing down the Drain, which in this case it needs removing from the blocked domestic gully Drain. The second most common reason is a foreign object has gone down the domestic gully Drain causing it to block and will need professionally unblocking."