Embattled gardening businesses were today granted a 28-day reprieve from the hosepipe ban.
Water companies moved to relax the rules following the wettest April on record which boosted river flows and eased the severity of the drought.
Thames Water said landscaping, turf and gardening firms in the South and East of England could now return to using hosepipes on newly laid turf and plants for a four-week period.
The decision was welcomed by horticultural businesses who feared the restrictions could lead to the loss of contracts and jobs.
Thames Water said about two-and-a-half times the normal amount of rain has fallen since it imposed a hosepipe ban on 5 April.
Richard Aylard, the company's sustainability director, said: "Our restrictions have caused real difficulties for some gardening businesses, so we are relieved to be in a position to take this step, which will enable them to carry on designing, landscaping, maintaining and building new features and gardens, while safeguarding their livelihoods and those of their employees.
"From today they will be able to water where necessary to get new gardens, lawns and plants established, and their clients will be able to continue this for up to 28 days."
The water company has agreed a code of practice with the Horticultural Trades Association (HTA), the Association of Professional Landscapers (APL), the Turfgrass Growers Association (TGA) and other landscape trade bodies to ensure supplies are not wasted.
It has vowed to lift restrictions for the rest of its 8.8 million customers as soon as possible.
"While the topsy-turvy British weather - record downpours after a record dry spell - has been working in our favour lately, we need to see how much water gets deep underground where we need it for what could still be a hot-dry summer," Mr Aylard added.
Another six water companies are granting businesses a reprieve from the ban, Thames Water said.
Tim Briercliffe, director of business development for the HTA and APL, said: "We are delighted that water companies have reviewed the restrictions on the landscape trade in light of the recent rainfall.
"Our members were facing serious business challenges as a result of the restrictions and this was likely to get worse with lost contracts and job losses. Much of this can now be averted thanks to this decision.
"Our members fully support the need for water efficiency and will do all they can to carry out water efficient practices, such as the use of drip watering systems, and to promote these to their customers."
Tim Mudge, chief executive of the TGA, said: "We're pleased that the water companies have recognised the important role turf plays in helping replenish our water supplies.
"The turf industry has already been hit hard by the hosepipe ban, with our members reporting a number of redundancies and reductions in sales of up to 60%.
"We hope the exemption will improve the situation as people begin to buy and lay turf again."
Earlier this month, the Environment Agency confirmed groundwater levels were still low across the country and parts of East Anglia and the South East remain in drought despite the downpours.
Environment Secretary Caroline Spelman has raised the possibility of standpipes returning to UK streets, saying heavy rain has not solved water shortages and that a wet winter is needed to ensure supplies returned to normal levels.