Horticulture industry figures have expressed concern about changes by the Environment Agency to the water abstraction licensing system, being made in the wake of drought and increasing pressure on resources.
Defra, the Welsh Government, the Environment Agency and Ofwat are working to design a new system, for which there will be a formal consultation in 2013. Changes are likely to come into effect in the 2020s.
The system will aim to "make a clear link between the amount of water available and the amount of water abstracted under licence", with growers likely to lose licences as a result.
Dove Associates consultant and Abstraction Reform group member John Adlam said: "Defra has been promoting water storage through its grants and workshops but that is only fine when you have an extensive land area."
He added that the Government wants all unlimited abstraction licences to become time limited in 2013 "taking away a right", which could lead to campaigns against legislation because "water is very, very important to horticulture and growers jealously guard it".
Adlam said drip irrigation is another big issue, with the Environment Agency proposing licenses for abstraction for this method of watering. Abstraction is currently free and not monitored.
"There is uncertainty where drip irrigation licenses will go."
He added that container-grown crops are unique in their requirements because they do not get rainfall so are dependent on watering and he is making that clear to Defra through the Abstraction Reform Group.
HTA business development director Tim Briercliffe said: "Our real concern with water is water abstraction licences. The Government wants to reduce licences in the future and suggest you can store more in a reservoir.
"But in ornamental horticulture the sites often do not have enough space for reservoirs. In West Sussex the glass often goes right up to the boundary. The Government needs to recognise that the issues faced by our industry are different to farming generally." He added that a dry winter would lead to more hosepipe bans in 2013.
NFU chief environment adviser Diane Mitchell said: "The NFU is involved in a number of the work packages, which gives us the opportunity to get involved. It is still very early stages and we are still waiting to find out what Defra's ideas are.
"Water is essential for our members - without it, a number of them wouldn't have a business. Water is critical to many agricultural businesses and security of supply is utmost in the minds of farmers and growers. Agriculture must have continued and fair access."
Shelley Common Nurseries owner John Middleton added: "Horticulture needs to plan well in advance if we are to lose our licences. We ought to be compensated for it so that we can re-invest in water-saving methods."