The underground lifeline

The designer of Warsaw's sewer system,  William Lindley, would have had no idea that the municipal sewer system he designed towards the end of the nineteenth century would be used as transportation for the military and civilian population, as well as a place of combat.

The existence of the municipal sewer system was responsible for the mysterious disappearance of the Old Town's defenders and civil population at the end of August 1944 during the Warsaw Uprising.

Around 6,000 people were able to flee to Warsaw's downtown district at the time, with another 1,000 making it to the Zoliborz district. During the capitulation talks, General von dem Bach admitted that he did not recognise the role of the municipal sewer system and its utility as a means of transportation and communication between Warsaw's city districts at first.

Indeed, the disappearance of the Old Town defenders signalled to the German forces that the problem with the municipal sewers was critical.

Resistance fighters began to use the sewers beneath Bonifraterska Street, the Gdanski Railway Station, and Stoleczna Street after the middle of August. The main sewer lines of the city converge at a sewer junction under the tracks of the Gdanski Railway Station: A1 and A2, which run beneath Okopowa Street; B, which runs beneath Marszalkowska Street; and C, which runs beneath the New Town district and Miodowa Street.

The city's sewer system was used to move resistance fighters between the Old Town, Śródmieście and Żoliborz districts.

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From then on, "sewer paranoia" gripped the German forces in Warsaw. The Germans were constantly concerned that resistance fighters would emerge unexpectedly from the sewers and attack German positions from behind.

The sewers connect at a depth of about 12 metres below ground. People could freely travel through the sewer tunnels because they were high enough.

The Germans must have noticed the traffic between the Old Town and the Zoliborz district because they lobbed grenades under the manhole cover over this sewer junction from time to time.

They'd lower a listening device into the sewer well and listen for any sounds coming from beneath.

This spot was even more unpleasant because in the A1 sewer they could encounter a sudden, rushing stream of water. A crossing was only possible by holding onto a chain or a rope placed at the spot. When crossing under that manhole with a patrol, it was hard for the insurgents to resist the desire to shoot up at the unwitting Germans above.

Breaking the dam

The last columns crossed from the Old Town on the night of 25th to the 26th of August 25th to the 26th. Germans began erecting a massive dam beneath Muranowska Street's manhole cover. The dam's purpose was to halt all sewer traffic and, worse, to significantly raise the water level in the sewers beneath Miodowa Street, Krakowskie Przedmiescie, and the New Town district. This would seriously hamper or even completely prevent, insurgent movement.
The dam was well-built, with wooden and steel beams, as well as sandbags. After about 2-3 days, word came from the Old Town district that the rising water level in the sewers had reached the area around Krasinski Square. The plan was then hatched to blow up the dam with demolition charges.

The idea for demolishing the dam came from three officers from the Home Army's Sabotage Section, who happened to be in the Zoliborz district, which they had arrived at during the last days of open sewer passage from the Old Town.

However, the Zoliborz district commanders did not want to undertake this mission without the permission of the Commander of Group North, Col. Wachnowski, who was stationed in the Old Town. The only way to communicate was by radio telegram sent through London. The message was sent to London by a small radio station in the Zoliborz district. The message was then relayed via radio to the Old Town radio station. (It was not possible to communicate directly via radio between the Old Town and the Zoliborz district due to technical issues.)

Unfortunately, messages could only be received and sent once per day in London. As a result, Col. Wachnowski's approval took some time to arrive. When the go-ahead was eventually given, the mission was launched as planned.

Coming from the Zoliborz district, a three-man patrol arrived at the dam and placed three kilogrammes of explosives and a timing device. The patrol then quietly withdrew and arrived safely back in the Zoliborz district unscathed.  Shortly afterwards, the detonation occurred at the planned time as the explosives detonated, blasting a hole in the dam.

After about a half-hour, water started to appear in the Zoliborz district's sewers, along with various materials that were now afloat in the sewer. The sewer passage connecting Old Town and the Downtown district was now clear.

The second dam cleared

Several days later, a group of Zoliborz "sewer rats" began systematic reconnaissance missions. The storm sewer beneath Krasinski Street was discovered to have an exit to the Vistula River. 
It was also discovered that the Germans had built a dam similar to the one on Muranowska Street beneath Marszalkowska Street.

The Zoliborz group acted quickly to demolish this dam. As a result, the sewer passage from the Zoliborz district to the Downtown district was soon opened. With the route now open, t he couriers then proceeded down this passage unhindered.

These intrepid scouts were usually 227th Platoon boy scouts – their youth an indication of the diversity of those resisting the German occupiers. The idea of laying telephone cables between the Zoliborz and Downtown districts had been floated in the middle of September and now with the route open it was a viable option.

The phone line went live on the afternoon of September 29th, the day the Germans launched their assault on the Zoliborz district. Unfortunately, the phone line was not used as a result of the assault.

The insurgent’s use of the sewers became increasingly sophisticated as time went by and they gained more experience. Signs were placed at major intersections and sewer junctions. Reserve food and medical stores were stashed at key points, such as wall cavities or sewer platforms. They became a base for long-distance reconnaissance missions to the Wola and Ochota districts.

Evacuating Old Town

On 31st August, due to mounting German pressure, the decision was taken to evacuate the Old Town area. This was to have taken place at 1:00 am but was delayed and did not commence until 2:30 am.

Chaotic scenes followed as distressed civilians blundered around in the dark, searching for one another, in the process inadvertently disrupting the assigned positions of platoons. 

An evacuation order was firmly established, with half-hour intervals carefully timed. The wounded were the first to enter the sewers, followed by some civilians; then insurgents without weapons, 150 German POWs, and finally armed Polish units. Medical personnel searched basements and ruins in the area for any wounded who could be transported before the attack began.

In desperation, the Polish army had to abandon the seriously injured and the majority of the residents of Old Town. The fear was that if even one man died while travelling through the sewers, his body would block the narrow passage, killing all the other defenders.

In an unfortunate turn of events, about 100 Polish insurgents and civilians who had fled through the sewers later emerged right inside a German compound (with the constantly shifting front line this was always a risk) and were shot on the spot. It had been a suicide mission. Tragically, these brave fighters willingly gave their lives to divert attention away from the other AK units making their way toward Centre City.

German responses

The Germans became increasingly fearful of the sewers, knowing that at any given moment, hostile insurgents could be lurking a few feet below them. According to General von dem Bach, he was never able to persuade his soldiers to descend into the sewers and continue the fight there. Instead, Germans began throwing grenades down manhole covers. They also dumped poisonous gas into the sewers in the Mokotow district. The effects of this gas were so strong that indicator candles - which were used to check the purity of the air - would not burn for several hours.

However, the Germans were sometimes forced to make limited use of the sewers themselves. They would transport collaborators, ethnic Germans, and Ukrainians through the smaller sewers beneath the Downtown district. These people would return to the German-controlled territory and join the city's exodus. Many of them did not return. Others did not arrive at their destinations and returned with fabricated information. However, the insurgents carefully guarded much of the sewers and were able to intercept and capture some of those working for the Germans.

Ultimately, the Germans were unable to overcome this "underground" resistance in Warsaw until the very end of the Warsaw Uprising. For the duration of the Warsaw Uprising, the sewer system was solely the domain of the Polish underground fighters.

The Germans were unable to cut off the Zoliborz district's sewer system from that of Warsaw's Old Town.


Throughout the uprising, the insurgents made effective use of the sewers. The availability of these hidden underground routes allowed the insurgents to cover large areas free from attack or interruption. They were used to evacuate crews from two city districts, Old Town and Mokotow, as well as to maintain communication between the city's besieged areas.  A telephone line was also installed in the sewers between the Zoliborz district and Downtown. 

The sewer, it turned out, played a significant psychological role in the fighting. The threat of insurgents suddenly popping up in German held territory, launching a violent attack and then quickly disappearing, was a cause of constant concern for the German commanders. Although they attempted to counter the insurgent’s actions, they were never really able to get to grips with the threat posed by the sewers.

Further reading