Smelly water.
 

Why would one faucet in my new house smell like rotten eggs when the others don't. The toilet water also smells the same/ They are both on the same wall. Any ideas or suggestions?

It's not logical it's the incoming water.

It may be when additional water is added the old water in the trap is activated.

In so doing it is emitting an odor, try adding a cup of bleach in the drain.

But also understand that un-filtered water has sulfur deposits, which has an unpleasant odor.

Call Warranty and ask them. They have talked to tens of thousands of people about everything imaginable. They are very helpful and since your home is under warranty, they can send the plumber who put in the plumbing to check it out, free of charge.

It's not your faucets, it is sewer gas that for some reason is escaping back into the home. Could be a couple of reasons. A dry water trap under the basin, a plugged vent pipe, to name two. The smelly water in the toilet is very strange.

I have seen that happen with the tub in our guest bathroom. It wasn't used for a couple of months and I believe the water in the trap evaporated. Once I ran the water for a few seconds to fill the trap the smell went away.

From Hair...

Welcome! sulphur dioxide
Hello! carbon monoxide
The air, the air
Is everywhere
Breath deep, while you sleep
Breath deep

You may have a failed Sturor Vent it most likely under the sink.