He said Labour wanted to "punish" workers and "make them choose between their jobs and the environment".
Woodhaven's owner, John Clarke, said his packing shed uses 150 cubic metres of water a day, and he has consent to use 3000 litres a day for irrigation.
"We need to wash our vegetables, we need to grow our vegetables, and we really don't want to have any tax just on water," he said.
Clarke presented Mr English and Mr Guy with gifts of vegetables, which Mr English announced would be donated to a local rest home.
He would not confirm whether he agreed with Mr Guy's recent comment to the Horowhenua Chronicle that the region's waterways were in "fairly good shape".
"There's been a lot of work done, with Horizons One Plan and so on, so there's plenty of detailed information about it," he said. "Now we have a system right across the country for measuring water quality."
On the topic of the pollution of Lake Horowhenua and other streams in the area, Mr Guy said there had been some significant funding grants from the Ministry for the Environment.
"Horticulture farmers around the very important catchment that feeds into Lake Horowhenua are working very constructively with Horizons Regional Council," he said.
Mr English fielded questions about National MP Simon O'Connor's earlier attack on Labour leader Jacinda Ardern, when he said she was concerned about youth suicide but was encouraging elderly and disabled suicide by endorsing euthanasia.
Mr English admitted that no National MP had attended the suicide prevention rally at Parliament the day before.
"I wasn't aware that there was no one there and there should have been," he said.
Mr English later visited Horowhenua College and was asked to hand out a certificate for Student of the Week to Jamie Lynn. Jamie's achievement was her work on the same suicide campaign which National had not turned up to.