Construction crews in the city of Newark are hard at work trying to replace old lead water pipes with pipes made of safer materials.

The replacement project comes after it was discovered that the drinking water in Newark was tainted with lead. The water source is safe, according to officials. But they say that the issues come from the lead service lines delivering water to the homes.

City officials say that about 800 lead lines have been replaced since March. Wednesday on Sandford Avenue, work crews were excavating, filling and removing lead water pipes.

"The method we're using is a trenchless method. We're trying to replace the pipe by not digging a trench from the water main, from the road, all the way to people's properties,” says environmental engineer Tosin Aedtutu.

Aedtutu says that the process entails using compressed air and a ground-penetrating device called the bullet.

"They shoot that in from the house down to the water main, thereby creating a hole so they can push in the new copper pipe and pull out the old lead pipes,” he says. "It takes a lot of skill because we have other utilities in the ground. There's gas lines, sewer lines. There's old water lines."

Bob and Lona Smith have lived in the area for 35 years. Their lead service line was replaced last week. But Lona Smith says that the effort may be too little, too late.

“They come out and fixed all this but the damage has been done. You got lead in you, it's there,” she says.

It takes about four hours to replace a lead service line. Officials say that it will take between 24 and 30 months to completely replace the 18,000 lead lines in Newark.