Most jockeys wouldn't dream of drinking five litres of water each day but Marlon Dolendo needs it to keep his sister's kidney happy.

Dolendo had a transplant three years ago after his kidneys failed, with his sister the generous donor.

He didn't think he would return to riding but some work in the stable reminded him where he belongs.

"There's nothing else I could think of to do," Dolendo said.

So six months after the transplant he was back in the saddle.

The northern NSW jockey has his first city ride since the illness aboard the Melissa Harrison-trained Road To Summer at Rosehill on Saturday.

Dolendo's new kidney is functioning well thanks to medication, regular specialist visits and a good splash of water - not something weight-conscious jockeys generally do.

But he's never had any problems with weight. He can eat and drink as much as he wants.

"I drink a lot of water now - at least four or five litres a day," he said.

Dolendo has another attachment to water.

He learnt to ride on water buffaloes in the sugarcane fields of the Philippines when he was a boy.

When he arrived in Australia he made an easy transition to horses through his friend Kim Jeffries, whose brothers Dale and Stephen were jockeys.

"She took me to the races. I didn't even know about racing until I met her."

Dolendo made his race debut in 1990, two years after moving to Australia with his family.

His Saturday mount Road To Summer is on a roll, stringing together five-straight wins, including an all-the-way success at Rosehill.

Dolendo, aboard for three of those wins, says the six-year-old is a real fighter.

"The more you give it up to him, the more he gives," he told AAP.

"He doesn't sprint that quick but he just keeps going."

Dolendo thinks he will be tested by a strong field on Saturday. Three of his opponents are from the dominant Chris Waller stable - You'll Never, Heart Testa and Said Com.