Police said the cause of the illness at the house in Thameside, Chertsey, was not yet known but there was “no indication there is a connection directly to the flooding” in the area.
Fifteen people, including officers, were taken to hospital as a precaution and nearby homes were evacuated.
All have since been discharged.
Of those, one had shown signs of illness.
A government spokesman said although the cause of the illness had not been found yet, there did not appear to be a wider public health risk.
They said the incident had been confined to the one house involved.
Ch Supt Dave Miller said the condition of boy’s parents, a man in his 40s and a woman in her 30s, was not thought to be life-threatening.
‘Vomiting and diarrhoea’
Asked about the potential connection to flooding in the area, the officer said: “We have a number of multi-agency meetings with senior partners from agencies that understand flooding and public health and at this stage there is no indication that there is a connection directly to the flooding.
“We haven’t had any kind of widespread casualties and the effects have been very localised. Clearly I can’t say that for certain because I’m not a medical expert and I’m not an expert in flooding but those are the facts at this moment.”
David North, 45, who was in the area taking photographs, said he saw a yellow hose hanging from the ground-floor front window of the house.
He added: “Whether it was pumping out water or something else, I don’t know.”
Police refused to be drawn on suggestions that carbon monoxide could have been to blame for the incident.
Ch Supt Miller said residents from properties near the house were advised to go to hospital to be checked as a precaution.
Other people nearby were told to stay indoors while inquiries took place.
Anyone local to Thameside who has felt unwell and showed signs of vomiting, diarrhoea and fever has been advised to seek medical assistance.
A police guard remained at the scene on Saturday and road closures are also still in place, preventing access to Thameside.
Emergency teams went to the scene just before 03:30 GMT after ambulance paramedics raised the alert.
The area had been badly hit by floods, and ambulance crews said they had difficulty reaching the property.