The government's inquiry into Havelock North's water contamination is focussed on a pond near the bores on Brookvale Road.
The inquiry was looking at how the town's water supply became contaminated, which led to more than 5000 cases of people ill with campylobacter.
Three deaths were linked to the contamination.
Counsel Assisting the Inquiry Nathan Gedye QC told the hearing a lot of focus would go on Mangateretere Pond near the bores.
Mr Gedye said three paddocks surrounding the pond were used for cropping, carrying livestock and predominantly sheep in the winter.
He put it to Hastings District Council water services manager Brett Chapman that sheep faeces from the surrounding paddocks were the predominant source of contamination, and Mr Chapman agreed.