Toilets at the newly-opened Terminal 2 at Heathrow have been fitted with sensors that anonymously count the number of people who use them.
The smart loos send alerts to cleaners after a certain number of people have entered.
The information is also sent to be analysed, allowing staff to see which toilets are used most often.
The sensors have been developed by embedded computing firm EuroTech using Intel technology.
Intel's director of smart cities and buildings Karen Lomas said that it was a good example of the way the so-called internet of things - technology that is embedded in everyday objects - could help improve daily life.
"We have all queued for the loo and the last thing I want to do is go into a dirty toilet," she said.
"Internet of Things technology should be used to improve decision-making and customer service."
The data from the sensors is sent to the cloud to analyse trends.
"It will show which toilets are being used more than others - which could in turn be used to direct people to loos that are empty," said Ms Lomas.
"Over a longer period of time there could be a repurposing of space for loos that are not used a lot and more loos put in places where people are going more often."
The system also monitors the time it takes for cleaners to arrive and clean the toilets which could raise privacy issues.
"It was already happening as a process with people having to sign a piece of paper so there is no change there. Most employees want customers to have a good experience," said Ms Lomas.