Epps, 23, and Cowan were in a Kiwi V6 500m crew which won gold. Cowan's fourth placings came in his V1 250 and 500m finals.
"That my first time as an individual paddler at world championship level so I'm stoked with that. There's this one really good guy but the rest of us weren't too far behind him ... I know what I have to do before the next sprint worlds which will be in Hawaii in 2020. It's all about getting better and better," Cowan said.
"I'll be back out on the water tomorrow [today]. We've got the long-distance nationals in Napier in October and it won't be long until the sprint nationals at Lake Karapiro in January again," he said.
Cowan heaped kudos on his coaches, Hawke's Bay's multiple world champion Maika Nuku and Rotorua's George Thomas.
At last year's long-distance world championships Cowan was in a six-person New Zealand adaptive crew which finished second to Australia in their 18km race.
Third-year paddler Macdonald, a solo mum with three boys who has a job with the Napier City Council and teaches self defence to youngsters, won gold in her V1 500 and 250m finals. Macdonald, 33, is no stranger to winning gold at world championship level.
She won gold and silver medals at her previous world sprint championships in 2016. Macdonald had to withdraw from last year's world long-distance champs after donating a kidney to her father.
She was confident of being in the medals prior to departure.
"My last sprint worlds was a last-minute decision for me because the team was short. This time we've had a bit more preparation ... we're a bit more of a serious team," Macdonald said last month.
Fourth-year paddler Epps took up the sport in an attempt to become more active after her stroke. She was also inspired by her nanny, Violet Gear, who still paddles at golden masters level.
The Hawke's Bay-based para manager for the Kiwi team, Honoria Ropiha, was thrilled with her team's haul of seven golds, five silvers and two bronze medals.
"The V12 500m crew, which had all three of our Bay paddlers, produced an amazing race to win their gold," Ropiha said.
Before the team left New Zealand Ropiha rated them as real contenders for medals and the paddlers backed her up big time.