Two men were killed in the attack, while five other people – including a woman and two children – were injured, a volunteer from the White Helmets rescue group said.
It comes amid a sharp increase in attacks by Moscow.
The attack targeted the pumping station near Ain Shib, west of Idlib, where the civilians had been living.
It comes amid a recent increase in Russian strikes on the Idlib region, swathes of which are controlled by Hayat Tahrir Al Sham, once affiliated with Al Qaeda.
Recent regime and Russian strikes in Idlib and fighting in the restive southern region of Deraa have marked the worst violence to hit Syria in recent years.
Russian forces also hit Ariha, south of Idlib, in overnight strikes, according to the Syrian Observatory for Human Rights, which reported that three HTS members were killed in a Russian strike on a rebel base earlier on Tuesday.
Five civilians were also reported wounded.
Russia is a firm supporter of Syrian President Bashar Al Assad and his regime, and has helped the government consolidate territorial gains and reclaim most of the country from rebel groups.
It killed 13 HTS fighters in strikes on the outskirts of Idlib on Monday, while three civilians were killed in an August 5 strike.
Moscow has also used its veto powers at the UN to block vital aid to millions of people in north-western Syria.
It vetoed a nine-month extension to UN aid deliveries through the Bab Al Hawa crossing in July, leaving the fates of millions of civilians uncertain.
Damascus later agreed to extend the agreement for three months.
Russia has also angered the US by harassing its drones and jets on counterterrorism missions in the north-east.
Several MQ-9 Reaper drones have been damaged by Russian aircraft, which have fired flares and struck US drones working as part of the anti-ISIS coalition.