DEWATERING SYSTEM VITAL

F.  DEWATERING SYSTEM VITAL  AC DEPENDENT?:
When a basement must totally rely on a dewatering system to keep water out, the power supply to the dewatering system must remain uninterrupted.  Since the electrical power system is often prone to failure during storms, an alternate power source is advisable.  Gasoline driven generators, DC battery backup units with battery charger packs, and pumps driven by domestic water line pressure are the most common backups.  The battery backup units are preferable from a dependability standpoint.  The water driven pumps have very limited capacity and gas generators often won’t start when needed the most.  The battery type can usually operate for 12 to 24 hours continuously or several days on an alternating basis.

Pumps with batteries as a backup usually automatically switch to DC power when the AC power fails.  Usually these systems incorporate a battery charger to rejuvenate the batteries automatically.  Some battery backup systems come with a single car type battery and some with two batteries. They range in price from a few hundred dollars to as much as a thousand.

NOTE: QUITE OFTEN, HOUSES EXIST WITH DEWATERING SYSTEMS without any real need.  Many building codes now require interior type dewatering systems.  These codes seem to stem from reactions to angry homebuyers’ complaints about water seepage.

WARNING: MANY INTERIOR PERIMETER SYSTEMS, INSTALLED AS RETROFITS, NEVER OPERATE. While small amounts of water reach the systems there is too little water present to trigger the pumps.

WHAT TO:  HOW TO:
The actual need for a basement sump pump will only be completely known when all weather conditions have been experienced.  Consider a four-day rain when the seasonal water table is quite high as a severe test.  It is wise to ask the sellers (in writing) about what water actually entered the basement.  Ask the neighbors and owners of similarly sited, built, and equipped houses for their experiences as well.

Most plumbers can install sump pumps but may need your guidance as to where and how deep to install them (See Fig. E).  Consult with an architect, building analyst, professional engineer, or soil scientist.