Build 42 Rain Collectors: Make Your Barrels Fill, Then Plumb a Sink Before the Shutoff

If you’re on Project Zomboid Build 42, the rain collector loop is still the same survival math: craft barrels, put them where the sky can hit them, and (optionally) plumb a sink so “drink water” stops being a daily chore. The two big B42 gotchas are version quirks (barrels that only fill when you’re nearby were addressed via B42 patch changes) and tooling (plumbing now leans on the pipe wrench in player reports). Jump to Quick-Start

Quick-Start

1. Loot the boring stuff first: garbage bags, nails, planks, a hammer/saw, and a pipe wrench.
2. Raise Carpentry enough to unlock the rain collector recipe in your B42 crafting/building flow (check the entry tooltip for your exact requirement).
3. Build a roof access (stairs or sheet rope) so you can place barrels safely.
4. Place the rain collector outside on a roof tile where rain can reach it (no roof over it).
5. Put the sink one floor below the barrel (same tile alignment), inside an enclosed room.
6. Right-click the sink → Plumb (pipe wrench in inventory) and confirm you can draw water.
7. Treat barrel water as unsafe unless confirmed otherwise: boil or purify when in doubt.

Info Card — project zomboid b42 rain collector “I’m ready” checklist
    [ ] Pipe wrench in inventory (not in a trunk)
    [ ] Barrel is OUTSIDE (rain can hit it)
    [ ] Sink is one floor below the barrel
    [ ] Barrel is on the same X/Y tile as sink
    [ ] Sink is inside an enclosed room (counts as “indoors”)
    [ ] You tested “Fill”/“Drink” and watched the water level change
    

What changed in B42 that actually matters for rain collectors

Build 42 is a moving target (unstable patches land fast), but if you only remember three things:

• Off-screen filling became a “real system”: B42 patch notes describe a fluid-container meta entity that makes rain barrels able to fill even when you’re not standing near your base. If you played an earlier B42 snapshot and got burned by “it only fills when I’m home,” that’s exactly the kind of behavior this change targets.
• Plumbing troubleshooting got louder: Community threads repeatedly point at pipe wrench + indoor checks as the reason “Plumb” doesn’t appear.
• Late-patch edge cases exist: Official B42.13 notes include fixes around rain collectors interacting with a sink’s fill submenu—so if you’re doing weird pre-shutoff testing, don’t assume every UI oddity is your fault.

Crafting the rain collector in B42 (without getting gaslit by the menu)

If you came from Build 41 muscle memory, B42 can feel like it hid your toys.

Step 1: Confirm you’re actually on B42 (unstable)

This sounds obvious, but a bunch of “B42 rain collector” confusion is just version mismatch. The B42 plumbing/rain-barrel behavior people talk about in threads is specifically around unstable patch numbers (42.x).

Step 2: Check the recipe tooltip instead of trusting your memory

Rain collector crafting has always been “basic materials, gated by Carpentry.” Player discussions around B42 still revolve around the same pain points:

• Garbage bags are the classic bottleneck (you either have them, or you’re suddenly living off bathtubs).
• The recipe might be in a different place in the B42 crafting/building UI than you expect.

Practical loot route: hit kitchens, janitor closets, trash bins, and commercial backrooms. If your run is already deep into “water anxiety,” consider breaking into an office/retail strip purely for dumpsters.

Step 3: Build two barrels, not one (future you will thank you)

One barrel is a proof-of-concept. Two barrels is a habit. Weather gaps happen; also, you’ll waste water on cooking, washing, and “I swear I drank that already” panic sips.

Placement rules: why your barrel collects nothing

Rain collectors aren’t smart. They don’t “sense rain nearby.” They need the game to consider them exposed.

The rule of thumb

If the tile is under a roof/ceiling, it’s not catching rain. Put the barrel outside on a roof tile.

Safer roof work

• Prefer stairs for repeat trips. Sheet ropes are fine, but they’re a “don’t sprint and don’t panic” solution.
• Clear zombies first. Rooftop placement is where you do the dumbest fall damage of your entire career.

Barrel staging trick (so you don’t haul a hardware store up a ladder)

1. Stockpile materials on the floor below the roof access.
2. Build/haul one barrel at a time.
3. Place barrels first, then worry about plumbing alignment.

Plumbing in B42: pipe wrench, indoor checks, and the “one tile, one floor” gospel

Plumbing is where Zomboid stops being a zombie game and becomes a petty building inspector simulator.

What you need

• A sink (kitchen/bathroom works)
• A rain collector barrel placed one floor above
• A pipe wrench (community threads explicitly call this out in B42 plumbing discussions)
• A room that counts as indoors (if the room isn’t enclosed, plumbing options can fail to appear)

The reliable layout

Put the sink inside. Put the barrel directly above it, outside.

Step-by-step: plumb the sink

1. Place the barrel on the roof tile.
2. Go inside, stand at the sink.
3. Make sure the pipe wrench is in your main inventory.
4. Right-click the sink and look for “Plumb”.
5. Use it, then test by filling a bottle or drinking to confirm the sink is drawing from storage.

Info Card — project zomboid b42 rain collector “Plumb” won’t appear
    Try these in order:
    1) Put the pipe wrench in your main inventory (not a bag-in-bag, not a car trunk)
    2) Confirm the room counts as indoors (finish walls/door, no “outside” holes)
    3) Confirm the barrel is exactly one floor above the sink (same tile)
    4) Confirm the barrel is outside (not under a roof)
    5) Relog/reload the save if you’re in MP and the context menu is desynced
    

“My rain collectors don’t fill unless I’m nearby” (B42 troubleshooting that isn’t superstition)

This complaint shows up often enough that it’s basically a rite of passage.

First: check your B42 patch behavior

SteamDB patch notes for B42.4.0 explicitly call out a fluid-container meta system meant to allow rain barrels (and similar containers) to fill even when you aren’t around. If you’re on an earlier unstable snapshot, you may simply be living in the “old rules.”

Second: confirm the barrel is actually exposed

Before you blame patches:

• Is it under any roof/overhang?
• Did you accidentally place it on a tile that counts as “indoors” (enclosed rooftop room)?
• Are you testing during actual rainfall (not “cloudy vibes”)?

Third: if it stopped filling after a crash

Community reports exist of barrels behaving oddly after crashes. The practical fix loop is:

1. Save/quit/reload.
2. Pick up and re-place the barrel (or rebuild if required).
3. Re-test during rain.
4. If you’re in MP, test on a fresh server restart.

Water safety: what to drink, what to cook with, what to stop trusting

Here’s the smart paranoia rule: assume rain barrel water is unsafe until the game clearly indicates it’s clean.

If you’re not 100% sure:

• Boil water in a cooking pot/kettle and store it in clean bottles.
• Use plumbed sinks for convenience, but don’t let convenience bully you into a stomach infection.

How many barrels do you need? (The “stop arguing with your future thirst” method)

Don’t plan for “a normal day.” Plan for:

• 2–3 days of rain drought
• A cooking binge (stews, boiling, cleaning)
• One “I got chased home and forgot to top off bottles” day

Rule of thumb:

• Solo: 2 barrels is comfortable, 3 is cushy.
• Two players: 3 barrels minimum if you cook/clean a lot.
• MP base with guests: build like you’re hosting a water-drinking convention.

When to consider mods/tools (and when to stay vanilla)

If you’re trying to keep a run “pure,” you can absolutely do rain collectors + plumbing in vanilla B42—just be strict about alignment and tools.

But if you’re:

• fighting placement rules,
• running MP with weird desync,
• or you want more flexible pipe behavior for base design,

…then plumbing-focused mods/tools (like Water Pipes–style plumbing extensions) can be a sanity saver. Use them like training wheels: to learn what “should” happen, then decide if you want to keep them.

The veteran advice nobody wants: test your water setup before the shutoff

Here’s the classic tragedy: you build the perfect rooftop barrel array… on day 12… and discover on day 14 that your sink won’t plumb because your “kitchen” is technically outdoors.

Do a dry run early:

1. Place one barrel.
2. Attempt one sink plumb.
3. Confirm you can fill a bottle from that sink.
4. Only then commit to your big rooftop project.

I’ve watched more survivors die from “base chores friction” than from hordes. Zombies are predictable. Your own impatience with plumbing menus is the real endgame boss.

Action Steps Recap: Loot a pipe wrench, build 2+ rain collectors on an exposed roof, align one barrel above an indoor sink, plumb it, and verify water behavior on your current B42 patch.

7) Patch-History (Collapsible)

Build 42 patch-history highlights for rain collectors & plumbing

Date	Change Note	Impact on early-game priorities
2025-02-11	B42 42.3.0 patch notes include fixes affecting rain-collector plumbing	Makes “plumb a sink” setups more dependable; worth re-testing older bases after updating
2025-03-04	B42 42.4.0 adds a fluid-container meta entity system so rain barrels can fill while you’re not nearby	You can roam/loot without babysitting your base during rain; reduces “stay home to catch water” behavior
2025-12-11	B42 42.13 notes include a fix where placing a rain collector above a plumbed sink could break a sink fill submenu before shutoff	Lowers the risk of weird sink UI behavior when experimenting early; encourages earlier plumbing testing