The Drains

The Drains is the second chapter of the second campaign, Death Toll. The Survivors begin inside of a safe house built within the entrance the drain systems of Riverside. There are tier 1 weapons, an ammo stash, and first aid kits sitting on a table. In this level, they must make their way through the drains, and to the next safe house.

Campaign
When starting from this chapter, the Survivor AI...
 * Bill usually will grab a submachine gun.
 * Francis usually will grab a submachine gun.
 * Louis usually will grab a submachine gun.
 * Zoey usually will grab a submachine gun.

When the Tier 2 weapons are found, the Survivor AI...
 * Bill usually will grab an assault rifle.
 * Francis usually will grab an auto shotgun.
 * Louis usually will grab an assault rifle.
 * Zoey usually will grab a hunting rifle.

Otherwise, they will keep the weapons they had when you started the campaign (see The Turnpike for a list of weapons they will grab there).

Unless something completely insane happened, like the Infected throwing out an ace before you can draw a card, the Turnpike should have been relatively easy, assuming you even went through them. Now that you're here, stock up on ammo and heal up if you need to. If you're starting here, just have everyone grab a first aid kit and a weapon. The pump shotgun has its advantages here, but you probably won't be keeping these weapons for long. Take what you can, and head out.

Once outside of the safe room, there are two drain openings, but both of them lead more or less in the same direction. The one on the right gives you high ground, however. Go whichever way you'd like (be sure to go down the ladder if you went to the right!) and there will almost always be some tier 2 weapons on the edge of the platform, with more ammo and potentially even a few pain pills on the other side. Change weapons if you'd like, get your supplies, and keep moving. At the end of the hallway of sorts you move into, there may be even more supplies inside of a closet. Once you have everything, you're probably ready for some fun, right? There's a floodgate in the next room. Get up there, while keeping an eye out for the pair of pipe bombs that generally spawn in a corner near the bridge. Just don't hit that button yet.
 *  This is one of the few most likely times for a Tank or Witch to appear. If you hear either before this, get ready as you will, and try to spare a Molotov for the Tank. 

Before you hit the button, it's usually best to get ready, maybe try to come up with something of a plan. Yes, the pipe bombs help to thin out or distract the horde, but they certainly won't kill them all. Only after everyone is ready should you press the button to lower the gate, thus summoning at least two waves of the Infected. Additionally, it's usually a good idea to wait out the horde, rather than running as soon as the gate comes down.

After you can cross the bridge and the zombies are dead, check a closet to the right of the path. There is ammo and a box of either first aid kits or pain pills, or maybe both. Take what you need and go on.
 *  This is another likely spot for a Witch or Tank to spawn. Trying to outrun the horde will probably make you run into these, and everyone knows it's a bad idea to run into either when you're not ready. 

Again, both of these pipes lead to the same area. There's a ladder up in the right corner, if you'd like to go that way, or you can look around a little and go up the set of fallen stairs which effectively make another ladder. Grass! You're almost out. If you need more supplies, there are usually more around the rooms here, and go outside. You'll head down what's moreover a grassy alleyway, which opens up onto a parking lot. Sometimes there are even more supplies inside of the dark rooms, and sometimes there are other nasty things.
 *  From here to the end are the last likely places for a Witch or Tank to spawn. If you haven't encountered one or the other at this point and you're doing well, look out. It's possible to just run to the safe house from here, though. 

The safe house marking the end of the chapter is inside of a caboose. Get in, shut the door, take a breather, and get ready for The Church.

Survival
Up and Over Method

After spawning on the map, incapacitate any survivors not under player control. Go up the ladder and grab a pipebomb. Crouch to the right of the bridge, on one of the metal outcrops. Below the bridge should be a crate. Throw the pipe bomb behind it and it should be catapulted up onto the ledge where you are (this make take a couple of tries). Using the box you should be able to reach a ledge in the edge of the wall (Incapacitating the other survivors stops them from breaking the box).

Start the round and get up onto the ledge. Follow the tunnel and take the first left. Jump down onto the gangway and follow it round to a ladder. Once down, go behind the ladder and follow the tunnel through to a much wider room. Across from where you enter should be a Safe room door. Get inside and shut the door. This makes it so that no infected can enter behind you. The only way infected can get in is if the tank breaks the door down. This is avoidable if no one stands in direct line to the door.

Trivia

 * A glitch in this level is when you are at the main chamber with the metal ladder surrounded by a rib of metal, if you try to go down that ladder while common and/or special infected try to go up, they will not be able to. The common infected will also automatically die once you move out of the way. This is a viable tactic to use against any Witches in the area.