Despite above average rainfall for parts of the South East during April and May, the drought situation remains serious in the region.
Two water firms have six months in which to use their drought orders
The Environment Agency said the wet weather was "great for our gardens" but had failed to properly replenish the important underground aquifers.
Most of the rain has been absorbed by plants or lost to evaporation.
But Mid Kent Water and Southern Water said recent rain meant they could hold off on implementing drought orders.
The orders, which can be used to ban non-essential water usage, are valid for six months after being granted by the government.
Howard Davidson, Southern regional director for the Environment Agency said: "We would like to see Southern Water and Mid Kent Water use these restrictions very soon to make the best use of the water we have.
"Heavy rainfall in May has been great for our gardens but has done little to ease the drought.
"Rivers have seen only small, temporary improvements to flows and the impact on groundwater has been poor."
Mr Davidson said around 70% of water supplies in the South East come from underground reserves which are running very low.
A Southern Water spokeswoman said: "If it keeps raining for the next couple of weeks, then it will start to replenish the aquifer."
The Consumer Council for Water commented: "We appreciate Southern Water's announcement that it will not make full use of the powers immediately."
However, it cautioned the water companies to consider their customers and not be "over-zealous" when imposing drought order restrictions.
Sutton and East Surrey Water was also granted a drought order this month and will begin using it from Saturday.