Drainage and septic tanks
How should a buyer separate a package treatment plant, a silent alarm and electrics the survey did not test when all three are mentioned together?
Keep the three apart. A package treatment plant is a packaged unit that treats sewage, a silent alarm is only a note that no sound was heard, and the electrics were not tested. Silence is not a failed plant and it is not a sound plant. The survey did not open the unit, did not run the alarm and did not inspect the electrical supply to it. A cesspool, which only stores sewage for emptying, is a different thing again. Nothing in the sentence has been decided as working or failed.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
A package plant usually needs power for pumps or blowers, and an alarm is meant to sound when a fault is detected by the unit's own kit. Hearing nothing on one visit does not show the alarm circuit, the beacon or the plant process. The surveyor is not there to certificate electrics, and this instruction did not include a test of the supply. The plant, the alarm and the wiring can fail separately. One quiet afternoon does not join them into a single result.
Ask the solicitor for the plant manual, any service contract and the last emptying or desludge note, and ask whether an electrical certificate exists for the supply. Those papers are not created by this survey. A drainage specialist can inspect the plant, and an electrician can test the alarm circuit, if you instruct them. Tell the lender no electrical test and no process test were done. Do not fold the silence into a claim that the tank is healthy.
What should you ask your surveyor?
- Was the alarm merely silent, with no test of the circuit?
- Did anyone open the package plant or only note that it was there?
- Has the electrical supply to the plant been left untested?
What are the typical next steps?
- Separate the plant, the silent alarm and the untested electrics.
- Ask the solicitor for the manual, service notes and any certificate.
- Instruct a drainage firm and an electrician if tests are wanted.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does a quiet alarm mean the blower is running?
No. Silence can mean the alarm is healthy, disconnected, failed or simply not triggered. This visit did not test the electrics and did not open the package plant. A running blower would be a separate observation, and it was not recorded as a test. Keep the alarm note as a limit, not as proof of treatment.
Should the lender be told the treatment plant passed?
No. Nothing was passed. The survey did not test electrics, did not sample the discharge and did not decide that the package plant treats sewage properly. A silent alarm is not that decision. If the lender asks, say the unit was noted and left untested, and point them to any service papers the solicitor holds.