Water System 101: Tanks, Pump, Taps & Hot Water — How It All Connects
Your Mars caravan water system is simple once you understand the flow: water tank → pump → taps/shower → hot water system (if selected) → outlets. Most “no water” issues come down to low water, the pump being off, or air in the lines.
This guide explains how the system works and the basic checks you can do before logging a support ticket. (Exact layouts vary by model/year.)
The basic components (what’s in the system)
- Fresh water tank(s): stores your water supply
- 12V water pump: pressurises the system when you open a tap
- Plumbing lines: deliver water to taps, shower and toilet (if applicable)
- Hot water system: heats water for hot taps/shower (if fitted)
- Filler inlet(s): where you fill your tank
- Drain points: used for storage prep, maintenance, or flushing
How it works (simple explanation)
Cold water
- You fill the tank.
- The pump draws water from the tank.
- When you open a tap, the pump activates and delivers water to the tap/shower.
Hot water
Hot water systems vary, but the idea is the same: cold water enters the hot water system, gets heated, then feeds the hot side of taps/shower.
- If your hot water system is OFF (or not heated yet), hot taps may run cold.
- After storage or draining, hot water systems and lines may need re-priming.
What controls the water pump?
Your pump is powered by 12V. If 12V power is off or low, the pump won’t run.
Common pump controls include:
- A switch on the main control panel
- A local switch near the pump (varies)
- A circuit fuse for “Water Pump”
Tip: If the pump makes noise but no water comes out, you likely have air in the lines or a valve/tank issue.
Normal behaviour (so you know what’s “okay”)
- The pump will run when you open a tap and stop when you close it.
- After filling from empty or after storage, it can take a little time to prime.
- Some pulsing can happen briefly while air clears from the lines.
- Hot water may take time to heat depending on the system.
Common problems (and the usual cause)
- No water at any tap: tank empty, pump off, fuse blown, airlock, or battery power issue
- Pump runs but no water: airlock, tank empty, pickup issue, valve position, or suction leak
- Pump keeps running: no water supply, air leak, or a leak in the system
- Water spurting: air in lines (often after filling or draining)
- Bad taste/odour: tank needs sanitising
Fast checks before lodging a ticket
- Confirm the tank has water (don’t trust the gauge alone if it looks wrong).
- Confirm 12V power is on and battery level isn’t extremely low.
- Confirm the pump switch is ON.
- Check the water pump fuse (replace with same rating only).
- Prime the system: open the cold tap and let it run until it flows steadily.
What to include in a support ticket (so we can help fast)
- Your model + year (and VIN/chassis number if available)
- Is the issue all taps or one tap?
- Does the pump make noise when you open a tap?
- Photo of your battery monitor (voltage/%)
- Photo of your control panel (pump switch area if visible)
- Short video: open tap + pump sound + flow (or no flow)