Base upgrades are the foundation of survival in Quarantine Zone: The Last Check. While inspections and moral choices define the experience, your run will fail quickly if your base lacks power, space, or stability.
Generator and Fuel Tank (Top Priority)
The Generator powers nearly every system in the base, including defenses, diagnostics, and automated facilities, and if it shuts down, the checkpoint becomes completely vulnerable. Upgrading the generator increases overall power capacity to support additional buildings while also improving fuel efficiency, allowing the base to operate longer with fewer refueling demands.
Fuel Tank upgrades are just as important. As your base grows, fuel consumption increases rapidly, especially during horde nights when all systems are active.
Upgrade priority:
- Fuel Tank upgrade early to increase storage
- Generator Tier 1 as soon as possible
Tip
Always maintain at least two to three days of fuel in reserve.
Generator upgrade options
Quarantine Facility Upgrades
The Quarantine facility allows you to isolate survivors with suspicious symptoms. Around Day 5, survivor numbers increase sharply. Without enough quarantine beds, you are forced into risky decisions that often lead to internal infections.
Upgrading quarantine increases bed capacity and stabilizes survivor flow.
Recommended Quarantine Capacity
Tent Housing Upgrades
Tents house survivors who have passed inspection and are waiting for evacuation. Evacuation quotas begin early and increase over time. Failing to meet them ends the run immediately.
Without enough tent space, players are forced to rush inspections or reject healthy survivors.
Tent capacity should always be maintained at least two slots higher than the current evacuation requirement to allow room for unexpected arrivals or recently cleared survivors. Tent upgrades should be planned based on upcoming evacuation quotas rather than the current population, ensuring the base is prepared ahead of time.
As a result, tent expansions are best prioritized shortly before evacuation deadlines to avoid last-minute shortages that can cause mission failure.
Tent housing interface
Science Lab Upgrades
The Science Lab plays a key role in improving inspection efficiency by reducing the need for constant syringe testing, which consumes credits and slows down survivor processing. As the lab is upgraded, it provides faster and more reliable diagnostics, allowing infections to be identified with greater accuracy while lowering long-term medical supply costs. Higher-tier upgrades also introduce passive research generation, adding ongoing value without additional effort.
Basic diagnostic upgrades handle standard detection needs, while advanced diagnostics help identify early-stage infections that are harder to spot through visual checks alone. Science Lab upgrades are highly cost-effective and are best pursued once essential power and housing systems are already stable.
Defensive Armament Upgrades
Defensive upgrades protect the base during zombie horde attacks. Early defenses are sufficient at first, but their reload speed and sustained fire become weaknesses as hordes grow.
Best early defensive upgrades:
- Reload speed
- Ammunition capacity
Damage upgrades are useful later, but consistent fire is more important early on. Defensive upgrades should never come before generator and fuel upgrades.
Drone weapon upgrade interface
Canteen and Hydroponics
As survivor numbers increase, managing food manually becomes increasingly inefficient and time-consuming. The Hydroponics upgrade addresses this problem by allowing the base to generate food automatically each day, reducing the need for constant resupply actions. This creates a more stable and predictable food supply, ensuring survivors remain fed without interrupting other critical tasks.
Hydroponics is especially valuable once the base population reaches double digits, as food consumption scales quickly and manual management can easily fall behind demand.
Recommended Upgrade Order
Days 1–2
- Fuel Tank upgrade
- Generator Tier 1
- Quarantine Tier 1
Days 3–4
- Tent Tier 1
- Science Lab basic diagnostics
- Quarantine Tier 2
Days 5–6
- Tent Tier 2
- Hydroponics
- Defensive reload or ammo upgrade
Day 7 and beyond
- Generator Tier 2
- Science Lab advanced diagnostics
- Additional defenses
For additional help with Quarantine Zone: The Last Check, be sure to check out our complete All Symptoms Guide for detailed inspection references, as well as our Beginner’s Guide for tips on getting started and avoiding early mistakes.