Hi Redrob. I'm very sorry that you had an awful holiday. And to reinforce what everyone has said... Did you have a personal nasty experience? Yes, the rumours are rife about "he who shall not be named", but unfortunately no proof has been put forward as yet.
As with many built up, busy resorts... there is a drugs' scene. But fortunately most people don't come across it.
We are aware of it in many resorts, but have never had it shoved in our faces, so to speak.
Please don't dismiss the whole of Lanzarote on what has been a bad experience for you. Maybe give Costa Teguise another go - or try Playa Blanca instead.
Celtygirl is right when she says that the council is going to invest. Yes, they have put aside a huge amount of money to imrpove the drainage system, and pavements of both Puerto del Carmen and Costa Teguise. This work has already started... and should improve things dramatically.
Don't give up on us hon! And I'd rather not have a volcano remove my clean, well-drain-supplied and happy home.