Subnautica Base Flooded? Separate Hull Strength, Breaches and Power

Identify which problem you actually need to solve

Treat structural strength, existing holes and power as separate checks. The community seabase reference describes a negative hull-integrity total causing hull breaches; it also says the breaches must be repaired after strength is raised. The developer's early-access base-building announcement describes flooding and a repair tool, but is historical guidance rather than a guarantee for every current release.

A powered base may still be flooded through a breach; a repaired base can still lack power. Do not assume adding solar power repairs a hole or that building a reinforcement automatically repairs every existing one. Keep an independent air return available while you diagnose.

References: Subnautica Wiki: Seabases · Unknown Worlds: base building announcement · Subnautica Wiki: Hull Integrity

Stabilize the structure before patching

The community wiki describes windows and base modules as structural costs and reinforcement, foundations and bulkheads as ways to increase the total. Depth can increase negative integrity penalties; the referenced positive reinforcement remains +7. Do not reuse another player's room budget as a guaranteed result. The base's build notification is the local check after each change.

With the Habitat Builder, select Reinforcement in the base-pieces menu and look for a compatible clear wall. The community original-game item entry lists one Lithium and three Titanium per panel. The community wiki lists +7 integrity per reinforcement; treat it as a reference and confirm the change displayed in your own save. This base wall is not the similarly named vehicle upgrade. If there is no free wall, inspect what can be moved or removed without losing access, and check the build prompt before dismantling anything.

1. Put a charged Habitat Builder and Repair Tool on your hotbar and plan an air return.
2. Read the integrity notification after a safe build or deconstruction; note its sign and value.
3. Inspect the builder's Reinforcement recipe and choose a compatible unobstructed wall.
4. Build the panel and confirm the displayed new total; add strength or remove a suitable weakening part until the total is positive.
5. Look for visible breaches throughout affected rooms and apply the Repair Tool to each until repaired.
6. Check that flooding recedes and check base power independently before treating it as an air stop.

References: Subnautica Wiki: Seabases · Subnautica Wiki: Hull Integrity · Subnautica Wiki: Reinforcement discussion index · Wikily: original-game Reinforcement

Worked budget: one panel is not always enough

Illustration only: suppose a construction notification reports -3 integrity and your installed game shows the community reference value of +7 for a base Reinforcement. One completed panel predicts -3 + 7 = +4, before any other change. Its listed cost is one Lithium and three Titanium. This does not predict whether old holes have been repaired or whether the base has power.

If the starting value were -8 instead, the same single panel would predict -1, still negative. Two panels would predict +6 and require two Lithium and six Titanium, assuming both panels are available, each actually contributes +7, and nothing else changes. Check the actual notification after the first panel rather than trusting the arithmetic across depths, versions or mods. A zero result is not a positive safety margin.

References: Subnautica Wiki: Hull Integrity · Subnautica Wiki: Reinforcement discussion index · Wikily: original-game Reinforcement

Repair holes and isolate the flooded section

Once the total is positive, swim through or around the affected areas looking for visible breaches. Use a charged Repair Tool on each damage point and verify it closes. The community reference says closed bulkheads can limit water transfer, but they do not stop new breaches indefinitely while overall integrity remains negative. If a section stays flooded, recheck for another breach and a closed bulkhead; don't assume one repaired hole was the only one.

If the total is positive and fresh damage keeps appearing, record the exact circumstances, including possible external impacts or creatures. The cited structural guide does not prove what damaged this particular save. Avoid attributing it to a creature without an observation.

References: Subnautica Wiki: Seabases · Subnautica Wiki: Hull Integrity · Unknown Worlds: base building announcement

Keep a useful evidence record

When the result differs, capture the platform, build, mode and mods; the displayed integrity before and after one construction; the recipe shown; and the number and position of visible breaches. Record power separately and whether water receded. A screenshot or short clip of the actual notification is more useful than describing a calculated prediction as a successful test.

Platform / installed version / mode / mods:
Integrity before -> after one build:
Panel recipe and wall selected:
Breaches found / repaired / remaining:
Power shown and source checked:
Water level after repairs:
Observed result and evidence:

References: Subnautica Wiki: Hull Integrity · Wikily: original-game Reinforcement

Before you play

• Read the actual integrity notification and restore a positive margin.
• Distinguish the base Reinforcement from the vehicle upgrade.
• Repair all visible breaches after stabilizing the structure.
• Check power and breathable air independently, with an alternate air return.
• Record platform and build when observed behavior differs.

Frequently asked questions

Sources & revision notes

Editorial revision: October 29, 2026; not a gameplay test date. The reference notes identify source limits and version differences.

1. Unknown Worlds: base building announcement (Official)

   Developer early-access announcement read October 29, 2026; describes structural integrity, flooding and repair. Historical source, not proof of current platform behavior.

2. Subnautica Wiki: Seabases (Community)

   Community indexed extract checked October 29, 2026 for negative integrity, repair, structural support and bulkhead behavior. Direct full-page fetch was restricted; not a player test.

3. Subnautica Wiki: Hull Integrity (Community)

   Community indexed extract checked October 29, 2026 for depth, component effects and reinforcement value. Direct full-page fetch restricted; no current-build number verified in-game.

4. Subnautica Wiki: Reinforcement discussion index (Community)

   Community indexed entry checked October 29, 2026 for +7 and compatible base wall types; current platform and version not specified.

5. Wikily: original-game Reinforcement (Community)

   Community item entry read October 29, 2026 for Habitat Builder, one Lithium and three Titanium. No installed-build recipe or construction verified.