House built on spring has special problems

Inspector's Eye

May 12, 2002|By Dean Uhler

I recently got a letter from Jodi Navid of Ellicott City, whose new house, she discovered, was built on a natural spring.

She noted that the spring pumps approximately 1,200 gallons of water every 24 hours, and she is concerned that water might get into her basement. She added that she has taken several precautions to keep her house dry. She has two sump pumps draining to back of the yard and two alarms if the pumps fail. Also she has two battery-backup sump pumps in case of power outage.

Basically, she wants to know whether there are any other suggestions for diverting the spring.

Whether the spring can be diverted depends on the lay of the land.

To divert it, there would have to be some place on the property where the surface of the ground is at a lower elevation than the basement. The low elevation would provide a place to which the spring water could be piped and discharged onto the soil by gravity flow, without using pumps. That would be the case if the house sat on a sloping site, where the ground falls off away from the house in at least one direction.

I suspect that the site does not fit this profile. If it did, the spring would probably have been diverted during construction. So it is possible that sump pumps are the only practical way to deal with the spring. Navid's two pumps can easily pump 1,200 gallons a day.

Most houses built today have sump pumps, though most don't work as hard as Navid's. They are part of the footing drain that is installed outside the foundation walls. The footing drain collects ground water from around the base of the foundation and drains it to the sump pump, which pumps it to the outside.

The only houses that can be built without a sump pump are those built on sloping sites where the ends of the footing drain can be discharged by gravity. Footing drains are required in all construction, whether or not there is evidence of significant ground water, and most run intermittently, if at all.

Navid's reliance on sump pumps is similar to that of homeowners who pay to have "waterproofing systems" installed in their basements after a wet-basement problem has developed.

Those homes use drain systems inside the basement and sump pumps to manage water that gets in. But even those systems generally deal only with intermittent, rather than constant, water flow, typically during or after periods of rain.

The protection provided by a single sump pump is sufficient for most people, and they don't worry too much about the occasional power outage or pump breakdown.

In contrast to most waterproofing systems, Navid's sump pumps deal with a water source that appears to be perpetual. This distinction might not be all that significant because in either case, malfunction of the sump pump or loss of electrical power for an extended period will result in a flooded basement. But homeowners with waterproofing systems usually get a reprieve when the rain stops.

Navid's predicament seems unfair. If 1,200 gallons is pumped out of her basement each day during a drought, how much water was there in the excavation during construction? Two days of water at a rate of 1,200 gallons a day would fill a 750- square-foot basement to a depth of more than 5 inches.

It leads me to wonder whether a lot of water was pumped out during construction and whether she was made aware that there was a ground water issue as soon as it became apparent. These seem like questions the builder should be asked.

Navid would not knowingly have built a house where all that stands between her and a flooded basement is sump pumps. Her best bet is to consult a civil or geotechnical engineer to evaluate the situation. With luck, someone can propose a better solution than the one she has.

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