Julian Aitken regularly tests the water underground and downstream from his feedlot.
"We are having no impact, in fact nitrogen levels are lower downstream than they are upstream," he said.
It has been on the former Waipawa River riverbed since the 1970s, where beef cattle are fed a variety of foods for three months over winter.
They were recently released to enjoy the spring flush.
"It is far cheaper to put them onto grass than to feed them supplementary feed.
"Supplementary feeding is a very normal farming practice, but obviously it is creating quite an issue now. With drones now there is nowhere to hide, which is good.
"We are trying to use best practice and look after the environment like everyone else."
What is not best practice is long-term supplementary feeding on one or two muddy paddocks.
"If you feed out on soil - farmland - then you can get pugging, which damages the soil. Plus you can get erosion of the soil which can go into a stream and is the main reason phosphates get into the stream, so it is far better to have it on a hard surface."
He feeds on a hard surface but because of the concentrated nature of the dedicated feedlot and its closeness to a waterway, people have suggested it is causing pollution.
"We have a ponding system there to pick up the effluent. Any effluent and dirt on the feedlot is scrapped off every summer. The surface is hard and stony and there is no evidence any is seeping in to the aquifer.
"We regularly test upstream and downstream and any aquifers and are totally compliant and are working with the Hawke's Bay Regional Council towards best practice but at the moment that feedlot does not need a consent. We are happy to get a consent if it's required."
He said farmers had as much obligation to ensure waterways remained clean as urban dwellers "but, if you look downstream from the towns, that is where the biggest build-up of nitrogen is and the problems it brings".
He said it was wrong to say Tukituki River water carrying bacteria had made its way into the Havelock North town-supply aquifer, a concern after thousands were recently affected by campylobacter.
"The regional council has stated the water in the Havelock aquifer is not contaminated. The Hastings District Council has not contested this.
"To imply farming practices upstream of Havelock North have affected the Havelock aquifer is without foundation."
With central government's inquiry not due to be complete until well into next year, it was "a long time for people to put out misinformation".
"Ninety-nine per cent of farmers want to look after our waterways and it is in our best interest to do so. That is why so many are fencing off and planting around our waterways.
"There are a lot of good things going on but there will always be some farmers, I imagine, that are using systems that are a bit old fashioned or they not worrying about the environment so much. It is up to the farming community and the regional council to police that."