B.C. is not yet officially in a heat wave, but many people, like these individuals in Vancouver, are not waiting to head to the beach. (CBC)

More hot weather forecast for B.C. is raising concerns about the water supply, air quality and even more forest fires, but it's not an official heat wave yet, according to CBC meteorologist Claire Martin.

"It's not officially a heat wave until we have temperatures six or seven degrees above the season average for three days," said Martin.

"We are not there yet, but we may be heading down that road," said Martin, who is forecasting temperatures will hit the high 20s C on the coast and the low and mid-30s in inland areas, throughout the week.

Air quality concerns

The ridge of high pressure boosting temperatures in B.C. is also trapping air in the Fraser Valley, raising air pollution levels across the Lower Mainland to between four and six — moderate levels on the 10-point air quality index.

Metro Vancouver air quality planner Laurie Bates-Frymel said the biggest problem is ground-level ozone.

"We've got a big high-pressure system over us now, so all the emissions we're emitting into the air are reacting together because of all the hot, dry stagnant air and they're creating ground-level ozone," said Bates-Frymel.

"Ozone isn't good for people to breathe in because it's an oxidant," she said, warning that children, the elderly and those with pre-existing heart or breathing conditions are at risk because of the air.

To help keep emissions down, Vancouver residents are being asked to do their part, said Bates-Frymel.

"We're asking people to reduce their emissions as much as they can without inconvenience. If they don't have to drive, please don't drive. If they don't have to use their gas-powered mower, then delay that for a few days and hopefully the levels won't get up to the levels we've predicted," she said.

Local industry has also been asked to reduce emissions while the air quality advisory is in effect, she said.

More lightning in the forecast

The hot weather is also combining with some moist air over some mountain areas and cold air aloft, leading to warnings that more severe lightning storms could hit several areas of the province in the coming days.

A series of thunderstorms that started last week has already caused hundreds of fires, according to fire information officer Kim Steinbart.

"We did experience a number of lightning storms in the past few days, which have contributed to about 300 new fires since Thursday," said Steinbart.

One storm, which passed over Vancouver on Saturday night, eventually sparked 40 small fires between Pemberton and Manning Park in southwestern B.C.

In the Kelowna area of the southern Interior, the fire department was put to the test when the lightning storm moved through the valley Saturday. The Kelowna fire dispatch centre dealt with 70 incidents in a two-hour period.

Fortunately, most of those fires have been remained small, she said, but there are about a dozen significant fires already burning across the province Monday, according to provincial officials.

"So far this year, we are above average for fire starts, but we are around average for the number of hectares burned [in] total," said Steinbart.

Already 370 firefighters have been brought in from Ontario, Saskatchewan and Manitoba to help out, and firefighting efforts are running over budget, hitting $68 million since April 1.

Campfire bans are already in place for most southern provincial parks, and many municipal parks also have smoking bans.

Sprinkler patrol

Watering restrictions are also already in place for many communities in southern B.C. that restrict the times and days people can water their lawns or wash their cars.

But anyone sneaking around trying to water their lawn in the dead of night in the Southern Interior town of Montrose could find themselves nabbed by a private security guard.

The village just east of Trail has hired a security firm to police its water restrictions out of fear people worried about their lawns are leaving Montrose vulnerable if there is a forest fire.

Mayor Griff Welsh says the village's water supply has dipped below the half-full mark and he's worried a disaster could happen. He's hoping people will water their lawns for only two hours a day and only at the times dictated by the village.

River water levels already low

On Friday, Environment Minister Barry Penner warned water levels for rivers in the Southern Interior and south coast are at record low levels, because of a combination of below-average snow this winter, and the dry, hot spring and summer weather.

Without rain in the forecast, officials say there is a strong possibility that some rivers in the South Interior and south coast may approach or exceed absolute record lows for August, leading to low water supply, lower than normal lake and reservoir levels, and reduced groundwater levels.

In some areas, fish and other aquatic organisms may be affected, warned provincial officials. Penner urged all B.C. residents to conserve water.

Water levels in rivers in northern B.C. are not as low, because there was more snow in those areas during the winter and several large storms passed over the region this spring and summer.

With files from The Canadian Press