Shepard, a retired aeronautical engineer in Worcester, knew better. But, he said, ``I thought if it wasn't giving us trouble, it could wait.''
Trouble is exactly what environmental and public health officials fear is percolating all over the Philadelphia region. They have ample reason to suspect that the suburbs in particular - where 20 percent of the homes, about 200,000, have septic systems - are fast becoming a minefield of malfunctioning and overflowing tanks, sending sewage seeping into gardens, fields, streams and wells, silently threatening anyone who partakes.
Add a rainy spring - as this surely has been - and a filled-to-the-gills system can go, literally, over the edge.
The untreated waste is a bubbling brew of bacteria, viruses and protozoa that can cause salmonella, dysentery, hepatitis A, giardia and general gastrointestinal distress.
In the last few years, nitrates thought to have come from septic tanks and their older cousins, cesspools, have been found in wells in communities stretching from Pemberton, Evesham and Woodland Townships in Burlington County; to Franklin Township, Gloucester County; to Towamencin Township in Montgomery County; to West Bradford Township and Unionville and Marshalton Village in Chester County. High nitrate levels can cause blood-oxygen deprivation in infants, a condition called ``blue baby syndrome.''
In Bucks County, residents have been hit by a series of sewage-related disease outbreaks. In one of the largest, in 1990, five families contracted hepatitis A after their Warrington Township neighbor's septic system overflowed and contaminated their wells.
``That's just the tip of the iceberg,'' said Lee Thomas, Bucks' director of environmental health. ``Because most people never test their well water, we don't know how many wells are contaminated. Because many people . . . don't pay much attention to their septics, we don't know how many are overflowing.''
Septic problems go undetected for another reason: People who drink sewage-tainted water usually just get upset stomachs - and blame it on something they ate.
The looming septic threat, experts say, lies not with the system's concept or design. A late-model tank ``can last a lifetime if it's properly maintained,'' said Pennsylvania Department of Environmental Protection sewer supervisor Glenn K. Stinson. ``But that's a big if.''
The culprits are homeowners. And only some are procrastinators like William Shepard.
Although 3,658 septic tanks sit in Philadelphia yards, urban dwellers tend to be a flush-and-forget-it breed. As the septically challenged have moved en masse to the suburbs, they have become notorious in public-health circles.
Many don't know how to use a septic system or how to maintain it.
Some don't know they have one.
At least once a month, Barbara Rigby, secretary for Wrightstown Township in Bucks County, gets a call from a homeowner complaining of sewage pouring into a backyard, the basement, the bathtub - and demanding that the township fix its sewer lines.
The township, she politely explains, has no sewer lines.
Jean Depew knew the house she bought in Malaga, Gloucester County, had a septic tank.
``But we didn't know what that meant,'' she said.
So the Depew family of five continued living as they had in Camden. Household cleaners, harsh detergents, thick bathroom tissue - all went down their drains.
In a few months, a pool of raw sewage was bubbling in the backyard. ``It came out of the ground just the way it went down the toilet,'' she said. ``It was embarrassing.''
The septic pumper who came to the Depews' rescue, Linda Cottrell, explained the limits and maintenance needs of a septic tank. Too often, she says, this is how septic education in the suburbs works, taught by a ``honey dipper'' in an emergency.
``Every day I get calls like this. They say they just moved from the city and don't know what to do and they've got sewage backing up into their house,'' said Cottrell. ``I'll tell you, I'm their best friend when I go out there and clean up the mess.''
Adding to the ooze are tanks that, like refrigerators, washing machines and stoves, just die of old age. Most of those installed in the first wave of suburban development 40 years ago are running up against their life expectancy, experts say.
Thomas Croisette's septic tank passed on at age 43.
A 76-year-old retired auto mechanic from West Rockhill Township, Bucks County, he had babied his septic system just as he babied his cars. The tank was pumped out every two years without fail, just like his cars' oil was changed every 3,000 miles.
In January, though, Croisette noticed a change in his well water. The county health department found one of his septic tank's pipes had collapsed, sending sewage into both his and his neighbor's wells.
``Our neighbors are mad at us,'' he said. ``But we didn't know. It's all underground. How could we see?''
* As suburban development marches on, planting residential outposts all along the region's frontiers, the percentage of homes with septic tanks is expected to increase.
This is not necessarily bad. Environmentalists say that septic systems, when maintained properly, are better for the ecosystem than municipal sewer systems. By allowing treated water to seep back into the soil, septic tanks replenish the aquifer; unlike municipal sewers, they do not use chemicals as cleaning agents, and when they do malfunction, they tend to cause far less environmental damage than a sewer main break.
Septic tanks also are less expensive for homeowners to install and maintain, compared with hooking up to a municipal sewer system and paying yearly bills, which can top $1,000 in some suburban communities. Barring any major problems with the site, installation of a septic tank costs between $2,000 and $3,000. To have it pumped out is about $150.
Many counties send information packets to new owners of homes with septic systems. However, officials say, some developers neglect to pass the packets along. And many residents, overwhelmed with other packets from schools, banks and community groups, often file the material away without reading it.
To force the message home, some Pennsylvania communities have not only instituted septic education programs but have passed ordinances requiring regular tank inspections and pumping.
In 1989, London Britain Township in Chester County became one of the first municipalities to create a ``pumping ordinance.'' Residents must show proof that they have pumped every three years.
Since 1991, Towamencin Township in Montgomery County has inspected all septic systems every three years and levied fines of $100 to $1,000 a day against any resident who fails to have his tank pumped every five years.
Montgomery County's tiny Bryn Athyn Borough encourages septic maintenance by subsidizing the cost of pumping. To spur similar efforts, the Pennsylvania DEP has offered funding. The programs, however, remain rare.
Public support is hard to come by, said Thomas, of the Bucks Health Department. ``They know it will cost them money if they are found to have a problem.''
In 1989, New Jersey's Department of Environmental Protection caused a stink when it required that all new septics be pumped out every three years.
``People felt like they were being overregulated,'' said Camden County Health Department sanitary inspector Bob Pirrotta.
Two years later, the agency bowed to public pressure and rescinded the program.
New Jersey state law allows municipalities to pass their own septic maintenance ordinances. None in the Philadelphia area has.
* Carol Lozzi could be a poster child for septic responsibility.
She bought her first home, a cute, two-bedroom rowhouse in Plymouth Township, Montgomery County, in 1985. The previous owner had raved about the safe neighborhood, the dead-end street that was perfect for children, and the yard.
``He said the yard was so fertile he grew tomatoes the size of two fists,'' Lozzi remembered.
She soon found out what powered his garden. On her first Thanksgiving there, a guest flushed the toilet and sewage flowed into the basement.
``We figured out that the person who lived there before us didn't pump [the tank] out,'' she said.
Her second home, in Worcester Township, Montgomery County, was inherited from a relative, who turned out to be a septic abuser, too.
Lozzi had to install a new system, an unexpectedly problematic process that cost $15,000 - and turned her into a septic zealot. Every two years, she gets the tank pumped, need it or not.
As for William Shepard, he has not been so easily converted. It has been two years since Montgomery County health officials visited his home and explained to him that his sewage system was on the fritz.
Shepard has yet to have the water in his well tested, although it sits just 50 feet from his septic system. He did get a new tank, but cleaning time already is here, and he still has not called a honey dipper.
``I guess I should think about getting it pumped out, huh?'' he said. ``But it hasn't given us any trouble yet.''