Short answer. Probably yes. Article 2191 makes proprietors responsible for damages caused by emanations from tubes, canals, sewers or deposits of infectious matter, constructed without precautions suitable to the place. The claim turns on how the thing was built, not merely on the fact that it is now leaking.
What the law says
By emanations from tubes, canals, sewers or deposits of infectious matter, constructed without precautions suitable to the place
Civil Code, Article 2191 — Other Liabilities of Proprietors. Read the full provision →
Constructed without precautions suitable to the place
The paragraph does not say that any leak is actionable. It reaches emanations from works constructed without precautions suitable to the place, which makes the manner of construction the heart of the claim. Suitable to the place is a relative standard: what is adequate on a large lot with deep soil is not adequate against a party wall on a slope draining towards you. So the questions are how close the tank sits to your boundary, how it was lined and sealed, what the ground does with water there, and whether any of that was considered when it was put in.
What the paragraph reaches
The wording is broad about the source. Tubes, canals, sewers or deposits of infectious matter covers a septic tank, but also drainage lines, open channels and accumulated waste, so do not get stuck on whether the structure has the right name. What matters is that something is emanating from a work on the neighbour's land onto yours. Note also that this is one of several liabilities the article imposes on proprietors, which means it is addressed to the person who holds the property rather than to whoever happened to dig the hole years ago.
Damage still has to be shown
Article 2191 gives damages, so you have to be able to point at harm rather than at a smell. Contaminated soil, a well or tank you can no longer use, dead plantings, a floor or wall that has to be broken up and rebuilt, a business interrupted, treatment in the household — these are things a court can put a figure on. Be careful about claiming beyond the harm actually suffered. And note that damages are one remedy: whether the tank must be rebuilt or moved is a separate question that this article does not answer.
Document it before anything is dug up
Photograph the seepage where it enters your lot and the condition of the ground, with dates. Have the water or soil tested by a laboratory, because a test result is what converts a complaint about smell into proved contamination. Establish where the tank sits relative to the boundary; a surveyed plan is worth more than an estimate. Keep every written complaint to the neighbour and to the barangay. If the household has been ill, keep the clinical records, and keep the invoices for cleaning, repair or hauling.
Related provisions
- Civil Code, Article 2176 — Quasi-Delict Defined (Culpa Aquiliana)
- Civil Code, Article 2199 — Actual Damages Must Be Proved