Did Hamas dig up EU-funded water pipes and turn them into rockets?

Question

A recurring narrative/allegation in debates about the current Hamas/Israel conflict is that Hamas has dug up EU steel pipes and turned them into Qassam rockets. The main sources for this appear to be this Telegraph article: EU funded water pipelines despite Hamas boast it could turn them into rockets which explicitly mentions that

The European Union helped to build more than 30 miles of water pipelines for Palestinians despite Hamas terrorists boasting of their ability to forge an arsenal of home-made rockets from pipes. [...]

In 2021 footage emerged of Hamas terrorists excavating pipes from the desert that were eventually fashioned into home-made rockets. [...]

Their main armament has been the Qassam rocket, assembled from industrial piping, makeshift rocket fuel of sugar and potassium nitrate fertiliser and commercially available explosives. [...]

While the Telegraph cannot independently verify the exact weapons used in the mass bombardment, it has raised fears over whether Western-donated building supplies could have been used to manufacture some of the munitions.

The rest of the article mostly details the EU-funded pipeline projects mentioned in the first paragraph, but it doesn't talk about whether Hamas specifically appropriated some of those. Also, it's not clear whether the title had been corrected for later on-line purposes. Press-reader has a different, more accusatory headline:

EU funded water pipelines that terrorists turned into rockets.

The DC-based National Pulse likewise titled their story

EU Spent $100M On Pipelines That Hamas Turned Into Rockets.

The Jewish Chronicle writes:

Hamas boasts that it uses EU-funded water pipes to convert into missiles.

Ibid for the Gateway Pundit:

Hamas Terrorist Group Turns EU-Funded Gaza Water Pipelines Into Missiles Used to Attack Israel. [...]

Hamas militants are seen extracting EU-funded water pipelines from the ground and then converting them into rocket components.

And there's the following Tweet and video posted by Lt. Col. (R) Peter Lerner showing a Hamas video digging up pipes and turning them into rockets. However, the accompanying tweet only says

People keep asking me where #Hamas have so many rockets from. Here’s the answer in a video they distributed. The world has invested so much for the people of #Gaza. Their leaders just don’t care.

So, clearly Hamas has dug up some pipes. But that tweet doesn't claim/explain what the [funding] source of the pipes is, other than vaguely referring to "the world".

This allegation has even come up on this site: Does Hamas divert humanitarian aid donations towards the military budget? where it is one of the claims in the only current answer.

1. Has the EU provided industrial piping and/or metal piping as shown in the video to Gaza
2. Is there evidence that Hamas has dug up EU-funded industrial piping and fashioned it into Qassam missiles?
3. Have missiles fashioned out of EU-funded water pipes been fired at Israeli targets?

Answer 1

According to an Al Jazeera documentary the water pipes for rockets are dug up from abandoned Israeli settlements:

Narrator: "The reclamation of the unexploded Israeli shells was not an easy task. There were several martyrs in this complicated production project. One of the pioneers and supervisors of this project, Ibrahim Abu Al-Naja, was one of the most prominent martyrs. While the plan to reuse the explosives in the Israeli shells was moving ahead, long water pipelines were found buried in the areas of the settlements from which Israel withdrew in 2005.

"This discovery turned out to be a qualitative leap. These pipes, which stretched from the liberated settlements in the west across the Israeli border to the east, had been hidden from the eye. For years, they served Israel in its theft of Palestinian water."

Abu Ibrahim, Commander from the Military Production Unit of the Al-Qassam Brigades: "In the belly of the Earth, we found large quantities of thick metal pipes. It was part of a network that had been used to steal Gaza's groundwater and pump it into the occupied lands. We discovered the plans for that network, and then we dug into the ground and pulled out the pipes, so that they could be used in our military industries."

Narrator: "In this documentary, we obtained exclusive footage from one of the workshops producing the long range Qassam missiles. These missiles have made distinct developments in their range, precision, and destructive power. These images show modern missiles being produced by recycling the unexploded Israeli shells, as well as the explosives they contained and the water pipes that were found."

[…]

Abu Ibrahim: "As a result of the ceaseless search efforts at land and at sea, we have accumulated hundreds of munitions and warheads, and dozens of tons of explosives and propellants. We have enough pipes to produce thousands of rocket engines."