Guide

Inspecting an Existing Radon System

Start with the manometer

It is the quickest check available and it settles the single most important question, which is whether the system is doing anything at all right now.

• Columns at different heights: the fan is pulling. Working
• Columns level: no suction. The fan has failed, lost power, or the pipe is blocked. The house is unprotected
• No manometer fitted at all: a defect. It is the only status indicator the system has, and its absence suggests a corner-cutting install
• Fitted somewhere you cannot see it, such as behind a boxed chase: a defect in practice, because nobody will ever look at it

If you are buying, photograph it. If you own the house, photograph it while it is healthy so you have a baseline to compare against later.

The rest of the walkthrough

1. Where is the fan? It must be outside the living space: attic, garage, or outdoors. A fan in a basement or a closet is a safety defect, because the pipe downstream of it is under positive pressure and any leak discharges radon-laden air indoors
2. Where does the pipe terminate? Above the roofline, above the eave, and clear of windows, doors and other openings, including a neighbour's on an attached house. A termination stopping short, or next to a bedroom window, is a failed installation whatever the test says
3. Is the pipe properly supported? Sagging horizontal runs hold condensate. Unsupported vertical runs rattle
4. Does it slope back to the suction point? Condensate should drain, not pool
5. Is there a system label? Standards require a description near the fan or manometer. Its absence suggests the install was not done to standard
6. Is there an accessible electrical disconnect? The fan has to be isolatable for service
7. Is the sump pit sealed, with a gasketed lid, sealed pass-throughs, and still removable?
8. Are visible slab openings sealed? Perimeter joint, penetrations, obvious cracks
9. Does the fan sound right? A low hum is normal. Grinding or rattling is not. See radon fan noise
10. Any sign of a second suction point? On a large or complex footprint, one may not be enough

The paperwork to ask for

• The post-mitigation test result, with a number and a date. This is the deliverable and it is the one most often missing
• Who installed it, and their PA DEP certification number, which you can verify yourself in DEP's public database
• The install date, which tells you where the fan is in its life
• The fan model and any warranty
• Any subsequent retests. DEP recommends one roughly every two years
• Any service records, particularly a fan replacement

An absent post-mitigation result is not necessarily a sign the system fails. It is a sign nobody checked, which is a different problem with the same solution: test it now.

Defects worth pricing into a negotiation

Finding	Severity
No suction on the manometer	The system is not working. Fan replacement or diagnosis
Fan inside the living space	Safety defect. Relocation
Termination below the roofline or near a window	Real defect. Pipe extension or rerouting
No post-mitigation test ever done	Unknown performance. Test before you rely on it
Fan over ten years old	Budget a replacement, plus a retest after
Open or unsealed sump pit	The fan is wasting capacity on indoor air. Lid
No manometer	No way to know it is running. Cheap to add
No label, no paperwork, unknown installer	Not a defect on its own, but test before trusting it

Test it regardless

Every item above is an inspection of the hardware. None of them measure radon. A system can pass every visual check and still leave a house above 4 pCi/L, because the suction field may never have reached the whole slab, or because the building has changed since.

A short-term kit under closed-house conditions is about fifteen dollars and answers the actual question. In a transaction, use a DEP-certified measurement professional so the result is defensible to the other side. See radon testing, radon and home sales and fans and maintenance.

Common questions

The house has a system. Do I still need to test?

Yes. A system's existence is not evidence that it works. Fans fail silently, pipes block, and houses change. A short-term test costs about fifteen dollars and is the only thing that answers the question.

What if the seller has no paperwork?

Then you have a pipe and a fan of unknown provenance. Ask for a current test as a condition, run by a DEP-certified measurement professional, and treat an absent post-mitigation result as a reason to test rather than a deal-breaker.

How old is too old for the fan?

Fans commonly last five to ten years of continuous running. Past ten, budget for a replacement even if it is running now, and factor that into the negotiation.