at we are planning a 30-in.-deep bed, it looks as though the effluent will not rise above a point 1 ft below the bed surface (Figure 7.4). Is this too much of a safety factor? What would happen if we increased the loading rate to 0.05 gpd/ft2? By going through the same calculations, we see that the saturated level in the bed rises to 25 in. - to within 5 in. of the surface. Now is the time to LOW-IMPACT SYSTEMS answer the questions you asked yourself before you began design- ing the system: how much money do you have and how often are you, your neighbors, and your local health department willing to put up with an overflowing ET bed? Let's assume that you decided to go with a loading rate of 0.04 gal/ ft2/day. And let's assume you have five people in your family. Because we are working with average monthly precipitation and average monthly evaporation, we can use average production of sewage effluent. For purposes of sizing the ET bed, assume an average production of wastewater of 45 to 50 gal per person per day, depending on whether you feel your family uses an average amount of water, or whether they may be willing to be conscious of their water usage and conserve a bit. Be sure not to size the ET bed smaller than would be required at two persons per bedroom, for you may wish to sell your house someday. If the loading rate is 0.04 gal/ft2/day, if the per capita contribution of sewage is 45 gal/day, and if there are five people, then 45 gpd per person x 5 people = 225 gpd 225 gpd 0.04 gpd/ft2 = 5625 ft SO the surface area of your ET bed must be 5625 ft2. If the price of this system is just beyond your reach financially, you could go with the higher loading rate. What you would be doing is increasing the probability of overflows during the winter months. But if you instituted a policy that when the effluent level in your ET bed reached, say, 20 in., everyone had to take "Navy" showers (wet down, turn the water off, soap up, then turn the water back on to rinse), or implemented other water-saving prac- tices such a