Police are investigating the incident that occurred at a property on Malpas Road in Willunga, which is believed to be an act of vandalism.
The McLaren Vale wine region vineyard has been passed down through three generations but its future is now in danger.
The damaged infrastructure supplied water to 80 hectares of land and filtered through the underground drain system from Wirra Creek to the property’s dam.
The family is working to repair the pipe but if they can’t it will cost more than $100,000 to replace.
“If we don’t have water to irrigate our vines then it’s just about finished and we’re at wits’ end unfortunately,” grape grower Izak Bruschi said.
“In our mind, it’s probably green activists and we’ve seen a rise of these sorts of people invading farms and causing malicious damage.”
Bruschi said if it was an activist behind the vandalism, they were misinformed as their drainage system was designed to benefit the surrounding ecosystem.
The wine industry has been facing tough battles with COVID-19 and the China trade ban, which was worth $1.2 billion to the industry.
Bruschi said it was causing a rollercoaster of emotions for the family.
“It would be quite devastating to say goodbye,” he said.
Police are urging anyone who saw anything suspicious in the area on Sunday or Monday to contact them.