There are about 31,500 HDB households here with two or more cars, and these families may soon have to fork out more for season parking charges.
The Housing Board (HDB), which is reviewing public parking rates, provided the figures in response to queries.
There are 981,100 resident HDB households in total, according to the 2015 General Household Survey.
HDB is mulling over differentiated season parking charges for residents who own more than one car and non-residents who use its carparks to manage demand. A resident's first car will get priority.
The Straits Times first reported about the government review of both short-term and season parking schemes yesterday.
HDB and the Urban Redevelopment Authority (URA) did not disclose the quantum of increase.
Public parking rates were last raised in 2002. Prices also went up in 1993 and 1989. In all cases, the increase was over 10 per cent.
One family with two cars hopes concessions can be given to those who use their cars for business purposes, instead of imposing a blanket increase.
Financial planner Koh Geok Lan, 53, said she uses her car to meet clients, while her husband uses his multi-purpose vehicle to make deliveries. They pay $90 monthly for season parking tickets per car.
"Most families that own more than one car need it for work. We wouldn't want to incur more costs otherwise," said Madam Koh.
Yesterday, drivers also raised concerns over how much parking rates would increase. The URA had said the review aimed to "right-price public car park charges and reduce the gap between the fees charged by private and public carparks".
In some areas in the city, hourly rates for private carparks during peak periods are more than double that of public parking spaces.
SIM University economist Walter Theseira said an increase of 10 to 20 per cent would not be unreasonable, given the length of time since the last review.
Parking rates here are underpriced for the level of economic development, he added.
"But any change would need to come with some transition period... It would be good to let people use their old coupons at the new face value," said Dr Theseira.
MP Lim Biow Chuan (Mountbatten), who sits on the Government Parliamentary Committee for Transport, said drivers were worried that rates could as much as double. "If it goes up by 10 cents extra per hour, I don't think people will make too much noise," he added, pointing out that public parking still needs to remain affordable to segments of the population.
The HDB and URA manage 607,000 and 24,000 parking spaces respectively.
But transport experts said increasing rates by a standard amount across the board is not the most efficient way to price parking.
Instead, parking rates could be dynamic, changing based on whether it was a peak period or in a busy area, said parking policy expert Paul Barter. "In some places, drivers could pay 25 cents per half hour, in others it could be $4 per half hour. We could do it that way."
He added that this was similar to how cities such as San Francisco price their parking - rates would be reviewed periodically to ensure occupancy targets were met.
"We set ERP (electronic road pricing) prices based on whether traffic is moving at the right speed. If speeds go up, the price drops and vice versa. Parking prices could be set the same way," said Dr Barter.