A full-sized two-story house was indeed seen floating on the San Francisco Bay, supported by multiple credible news reports confirming it was being transported on a large barge.
A full-sized house was seen floating on the San Francisco Bay

Mystery surrounding why there was a full-sized two-story house floating in San Francisco Bay - US News - UNILAD
Source: unilad.com
Key Evidence
The U.S. Coast Guard's confirmation that the house floated on a barge provides a clear causal mechanism for how a full-sized house could be seen floating. Multiple news outlets documented the event with photos and videos, confirming its authenticity.
What the Evidence Shows
The claim that a full-sized house was seen floating on the San Francisco Bay is accurate. Multiple independent news sources and eyewitness accounts confirm that a two-story house was observed floating and being towed across the Bay. The U.S. Coast Guard clarified that the house was able to float because it was situated on a large barge, which provided the necessary buoyancy and stability for transport.upi.comupi.comWatch: Two-story house floats through San Francisco Bay
Reports describe the logistical challenges of moving such a heavy structure through the Bay's tides and currents, emphasizing that this was a planned and controlled movement rather than an accidental or mysterious event.sfgate.comsfgate.comEntire home spotted floating across San Francisco Bay
youtube.comyoutube.comMystery house is floating in San Francisco Bay Videos and photos from reputable news outlets and local observers further corroborate the sighting. The event attracted public attention but is explained by standard maritime transport practices for moving large structures.
There is no evidence suggesting any misinformation or exaggeration in these reports.