Three water companies are seeking to impose severe restrictions on businesses as the drought continues across most of England putting rivers and wildlife under huge pressure.

Golf clubs and private schools could be barred from using mains water to irrigate playing fields and courses, and commercial car washes stopped from operating, under "non-essential use bans" being sought by the companies.

Eleven areas of England are still in drought, rivers are suffering from low flows, groundwater levels are declining and reservoir levels are at 54% – 21% below what is expected in the autumn.

Yorkshire was the latest area to move into drought status on 9 October. Parts of Wales are experiencing the first signs of drought recovery after the whole country was declared in drought in July.

Nineteen reservoirs or reservoir groups in England and Wales are less than 50% full, and eight are exceptionally low, up from five in August The Met Office says above-average rainfall is needed over a sustained seven-month period to bring all areas out of drought. But last month England received about 65% of its typical September rainfall, with eastern and southern areas experiencing the greatest deficit.

Businesses in drought-hit areas have been excluded from the hosepipe restrictions imposed on the public for the past three months. But South East, Southern and South West Water have applied to extend restrictions on water use to businesses via non-essential use bans in parts of their regions. If granted, water restrictions can be placed on golf clubs, private schools and commercial car washes to cut water use. Power hoses in car washes can use up to 25 litres of water per minute.

Permission from the Department for Environment, Food and Rural Affairs (Defra) is required, but the government has yet to respond to the water companies' requests.

Pressure on wildlife and the environment from the drought is continuing. River flows in seven areas in England are exceptionally low, according to the latest Defra figures, affecting habitats, fish and wildlife. They include the River Derwent in the north-east, the rivers Yare and Ely Ouse in east England, and the River Tone and the Hampshire Avon catchments in south-west England.

When river flows fall to low flow levels they can take years to recover, with potentially severe effects on fish spawning and river health.

Mark Owen, the head of fisheries at the Angling Trust, said: "When rivers and fish are suffering from the ongoing effects of a severe drought, the Angling Trust supports further restrictions on non-essential water use, alongside urgent action to reduce huge leakage from water companies and unsustainable abstraction from rivers.

"We must continue to reduce unnecessary demand for water. It makes little sense to ban people from washing cars at home while commercial car washes can continue operating." In Hampshire, where the chalk aquifer is exceptionally low, Southern Water is seeking a drought order that would allow it to draw water from an internationally prized chalk stream and rare salmon habitat, even at levels below what is deemed ecologically safe. Southern said it was applying for the permit for the River Test owing to "a clear threat to supplies" in Hampshire and the Isle of Wight.

The company is seeking a non-essential use ban on commercial premises and businesses to reduce demand as it seeks to draw more water from the Test.

As they seek permission to put restrictions on businesses' water use, South East Water and South West Water have been allowed to alter the amount of water they draw from rivers to try to conserve water in their reservoirs.

The Ardingly reservoir, near Haywards Heath in West Sussex, which serves 280,000 people, is exceptionally low, holding 1.05bn litres of water. Its total capacity is 5.2bn litres.

In the south-west, Colliford reservoir on Bodmin Moor, which serves 255,000 households in Cornwall, is 37% full, holding 10.68bn litres against a total capacity of 28.5bn litres. Wimbleball in Somerset, which provides water for 390,000 people, is 18% full, with 3.8bn litres against a total capacity of 21.3bn litres.

Sam Bottomley, South West Water's director for drinking water services, said the region was entering a critical phase of an exceptionally prolonged drought.

"Every day we continue to draw on our reservoirs to keep water flowing to homes, businesses and communities while river flows remain below the levels needed to support public water supply," he said.

"Many people understandably think a drought is over once it starts raining. In reality, recovery takes much longer.

"Some rivers still remain at their lowest levels and with no significant rain forecast for the coming weeks, the immediate challenge is reducing demand and preserving enough stored water to maintain supplies until river flows and reservoir levels recover."