A Hyde Park basement that tested at 14 pCi/L: what happened next

The starting point

A homeowner in Hyde Park ordered a hardware-store charcoal kit after their realtor mentioned radon during a refinance appraisal conversation. They placed the kit on the basement floor next to the laundry, ran it for 48 hours per instructions, and mailed it back. The lab return: 14.2 pCi/L. EPA action level is 4.0 pCi/L. The homeowner called us the next morning.

The home is a 1924 American Foursquare with a stone-and-mortar basement, partial floor sealing from a 1990s waterproofing job, a sump pit in the southwest corner with a passive (no fan) vent pipe stubbed in by the prior owner, and a forced-air gas furnace in the basement. Two children live on the second floor; a home office is set up in the basement. Total exposure picture: high.

What the on-site assessment found

The partner-network mitigator did a 45-minute walkthrough on day two:

• The sump pit lid was unsealed (gap around the pipe penetration).
• Two visible cracks in the slab near the furnace, each running 3-6 feet.
• The "passive" vent stub had been capped with a PVC cleanout plug. No fan, no draw, essentially decorative.
• Mortar joints in the stone wall had air movement detectable on a smoke pencil at three points.
• The dryer vent ran horizontally through a wall penetration that was never re-sealed after install.

The diagnosis: high soil-gas infiltration via multiple paths. Sealing alone would knock 10-20% off the reading at best per EPA guidance. Active sub-slab depressurization was required to clear the EPA action level.

The fixed-price quote

The partner contractor wrote a $1,840 fixed quote that morning, including:

1. Core-drill suction pit through the slab adjacent to the existing sump 2. 4-inch PVC stack routed up an interior closet chase to the attic, then through the roof with proper boot flashing 3. Inline radon fan (Radonaway RP145, rated 145 CFM at this stack length) 4. Sealed sump pit lid with rubber gasket and silicone 5. Polyurethane caulk on both visible slab cracks plus the wall penetration around the dryer vent 6. Manometer and labeled fan-failure indicator at the basement ceiling 7. Dedicated 15A circuit run from the panel 8. 48-hour post-install verification test 9. 12-month follow-up retest

Quote good for 30 days. No "we found more on the day, here is a change order." Fixed.

Install day

Crew arrived at 7:45 AM. Core drill started at 8:10. By 11:30 the suction pit was excavated and the stack was rough-routed through the closet chase. Lunch break. By 2:30 the fan was mounted on the exterior wall in a ventilated cabinet, the wiring was on a dedicated circuit, and the manometer was reading 0.85 inches water column of negative pressure, healthy for this configuration. The crew walked the homeowner through how to read the manometer (the U-tube fluid should sit asymmetrically; if it equalizes, the fan failed) and what the fan-failure light looks like.

Total time on site: 7 hours. Total mess: a small pile of slab dust, vacuumed at end of day.

The 48-hour retest

A continuous radon monitor was placed in the home office (the same spot as the original charcoal kit). 48 hours of logging, closed-house conditions documented. Result:

0.7 pCi/L average.

Drop of 95% from the pre-mitigation reading. Below the 2.0 pCi/L EPA-recommended post-mitigation target, well below the 4.0 pCi/L action level. Lung-cancer risk for the household drops to general-population baseline per the EPA's published risk tables.

Things this case shows that homeowners often get wrong

• Sealing alone is rarely enough when the source is a network of soil-gas paths plus a leaky sump pit. The sealing you'd need to do to stop infiltration via stone-mortar joints is impractical without depressurization.
• A passive vent stub does not equal mitigation. Hundreds of Cincinnati homes have a piece of PVC sticking up through the slab and a homeowner who thinks "that's the radon system." Until a fan is wired in and pulling negative pressure, it is decorative.
• Real-estate timelines work. From homeowner call to post-mitigation retest below 2.0 pCi/L was 11 calendar days. Most lender contingency windows fit comfortably inside that.
• Same-day visit + fixed quote is normal. The variation in pricing between contractors is real, but the structure of the quote (fixed, written, valid 30 days) should be consistent. If a contractor wants to start work without a written number, walk away.

What the homeowner paid

Total out the door: $1,840. Annual electricity for the radon fan: about $80 ($6-$8/month). Resale-value impact (per Cincinnati MLS comparables for documented post-mitigation under 2.0 pCi/L): typically $5,000-$10,000 favorable, especially for buyers who tested as part of inspection.

What to do if your test comes back high

If your initial reading is above 4.0 pCi/L, the math is simple. The cost of mitigation in Cincinnati is consistent and bounded ($1,200-$3,500 in most cases). The cost of not mitigating is cumulative lung-cancer risk plus a price-renegotiation problem at sale. Phone consultations are 10 minutes and free.