Sewage Exposure and the Hygiene That Prevents Illness

Why this matters

Every drain tech has had the "stomach bug" two days after a main-line backup, and most shrug it off as part of the trade. It mostly is not bad luck. Sewage carries a predictable list of germs that get into people by a short list of routes, and nearly every case traces back to a hand that went to a mouth, a cut that was not covered, or dirty clothes that rode home in the cab. The protective habits are cheap. The failure is treating sewage as dirt instead of as a source of infection.

This card explains what is in sewage and how it gets in. The step-by-step routine for a sewage call is its own procedure. See related: The Sewage Contact Hygiene SOP.

What is in it

Raw sewage is human waste plus whatever else went down the drain, and it carries whatever the people upstream were carrying. The germs fall into four groups:

Two things make this worse than ordinary dirt. First, the dose needed to make someone sick is small for several of these: a trace on a finger is enough for norovirus or Shigella. Second, the delay hides the cause. A tech sick on Thursday from Tuesday's call blames Wednesday's lunch.

What this card does not cover. Gases from sewage, hydrogen sulfide above all, are a separate and faster hazard in tanks, pits and sewers, where they can kill. That belongs to confined space rules, and nobody enters a septic tank, sewer or wet well under this card.

The five ways it gets in

1. Hand to mouth. This is most cases. The gloved hand that adjusts a water bottle, the bare hand that eats a sandwich before washing, the cigarette, the fingers that rub an eye or wipe a lip. The germs above mostly cause illness when swallowed, and hands are how they get there.

2. Splash to mouth, nose and eyes. Jetting and rodding a line, pulling a cleanout plug on a backed-up line, or pumping out a flooded basement throws droplets several feet. A splash to the lips is swallowed; a splash to the eye can cause infection. This route is controlled by eye and face protection, not by gloves.

3. Breaks in the skin. A cut on a knuckle, a split cuticle, a blister, a scratch from a cable. Sewage in a break in the skin can cause a wound infection. Any cut on the hands is covered with a waterproof dressing before gloves go on, and a glove that tears gets replaced, not taped.

4. Fine spray breathed in. High-pressure jetting and some pumping make a fine mist. Most of what is breathed in is then swallowed, so it adds to route 1 and 2. A face shield over safety glasses cuts the droplet load; a respirator matters in heavy spray and is worn only under a written program per OSHA's 29 CFR 1910.134.

5. The truck and the house. Germs ride on boots, gloves, clothing, tools, phones and steering wheels, and reach the tech hours later, and the tech's family that night. This is the route that turns one exposure into several.

Why sanitizer is not the answer

Alcohol hand sanitizer is a backup, not a wash. It works poorly on hands that are visibly dirty or greasy, which describes every hand that has been in a drain, and it is less effective against norovirus and Cryptosporidium, two of the most common sewage germs. The answer is soap, running water and 20 seconds of scrubbing, including under the nails. That means carrying water to the job: a jug with a spigot, liquid soap and paper towels at the tailgate, because the customer's sink is not where a tech should be washing sewage off.

Sanitizer earns its place after washing, or where washing is truly impossible, as a stopgap until soap and water.

The clean side and the dirty side

Most of the hygiene for a sewage job is geography: keeping the dirty side of the job from ever reaching the clean side.

TRUCK, TOP VIEW
+------------------+-----------------------------------+
| CAB  = CLEAN     | BODY / BED  = DIRTY               |
| phone, lunch,    | jetter, cables, boots, gloves     |
| water bottle,    | bin, bagged dirty clothes,        |
| clean clothes,   | disinfectant, spare gloves        |
| paperwork        |                                   |
+------------------+-----------------------------------+
        ^                          ^
   CAB DOOR                    TAILGATE = WASH POINT
   enter only after:           water jug, soap, towels,
   gloves off, boots off       trash bag for gloves
   or covered, hands washed

The rule that follows from the drawing: nothing that touched the job goes in the cab, and nothing from the cab goes to the job. The phone stays in the cab or in a sealed pocket under coveralls. Lunch and drinks stay in the cab and are reached only after washing at the tailgate. Soiled clothes go in a bag in the body and are washed at work or separately in hot water, never in the family load. Boots get rinsed and stay in the body.

The customer's side of the same germs

The routes that reach the tech reach the household too, and the tech is often the only person on site who knows it. Three habits keep the job from leaving an exposure behind:

• Do not track it. Boot covers or a drop cloth path from the work area to the door, taken up and bagged at the end. Sewage carried across a carpet on a boot sole is a carpet that now carries the germs in the table above.
• Do not wash in their sink. A kitchen or bathroom sink used to rinse a sewage glove is a contaminated sink in a room where food is made or teeth are brushed. Wash at the tailgate.
• Say what is left. If sewage spilled onto floors, walls or belongings, tell the customer plainly that the area is contaminated, that children and pets should stay out of it, and that cleanup of soaked carpet, drywall and furnishings is a job for a water damage restoration contractor unless your shop does that work. Write that you told them in the job record.

Vaccinations and other medical questions

Techs ask whether there is a shot for this. The honest answer has two parts. A current tetanus booster matters for anyone in a trade where cuts get contaminated with soil or sewage, and many people do not know when their last one was. Beyond tetanus, whether a sewage-handling tech should be vaccinated against anything else, such as hepatitis A or B, depends on the work and the person, and public health guidance for sewage workers does not answer it the same way for everyone. That question goes to an occupational medicine physician, not to the shop and not to this card. A shop with several techs on drain and septic work can set up one occupational health visit to settle it for the crew.

See a doctor, and say you work with sewage, for fever, bloody diarrhea, vomiting or diarrhea lasting more than a day or so, signs of dehydration, a cut that turns red, hot, swollen or painful, or yellowing of the skin or eyes in the weeks after a job. Telling the clinician about the sewage contact changes which tests they order.

Worked example: one basement backup, three routes

The job. A drain tech in Ohio clears a main-line backup through a basement floor drain. About an inch of sewage covers part of the basement floor. He wears rubber boots, nitrile gloves and safety glasses. No face shield.

The day, from his own account afterward:

• He pulls the cleanout plug on the backed-up stack. Sewage spurts out under pressure and splashes across his chin and lips. He wipes it with the back of his gloved hand.
• An hour into jetting, he is thirsty. He walks to the truck, holds his water bottle with his gloved hand, and drinks.
• His left glove tears on a cable at the knuckle. He keeps working and swaps gloves at the end of the job. There is a small scratch under the tear.
• At the end, he pulls his gloves off, sanitizes his hands, eats lunch in the cab, and answers two calls on his phone, which spent the morning in his coverall pocket.

Two days later he has sudden vomiting and diarrhea, starts feeling better after about two days, and misses two days of work. Separately, the scratch on his knuckle is red and puffy on day three and he gets it seen.

Tracing it. Three routes, each one an exposure on its own:

1. Splash to mouth at the cleanout, made worse by wiping with a contaminated glove. A face shield over his glasses was the control.
2. Hand to mouth, twice: the gloved hand on the water bottle, and lunch after sanitizer on unwashed hands, plus a phone that had been in a dirty pocket. Soap and water at the tailgate before the bottle and before lunch was the control.
3. A break in the skin under a torn glove. Replacing the glove at once, and covering the scratch with a waterproof dressing, was the control.

Two days from the call to the first symptoms fits norovirus, but nobody can say which of the routes did it, and the point is that any one of them could have.

What the shop changed: face shields on every drain truck and required when opening a cleanout on a backed-up line; a water jug, soap and towels at every tailgate; drinks and phones stay in the cab until after washing; a torn glove means stop, wash, dress any cut, new glove.

What would change the answer. A septic tank or sewer manhole adds the gas hazard, and the first control there is staying out of the space, not hygiene. Floodwater in a basement after a storm is sewage plus fuel, chemicals and electrical hazards, and needs more than this card. See related: Floodwater Exposure for Any Trade. And if the backup was in a home where someone was sick with a stomach illness that week, the dose in the sewage is higher, which is one more reason the routine cannot depend on knowing that.

References

• CDC/NIOSH, Guidance for Reducing Health Risks to Workers Handling Human Waste or Sewage
• CDC, handwashing guidance, including the limits of alcohol-based sanitizer on soiled hands and against norovirus and Cryptosporidium
• OSHA, 29 CFR 1910.134, respiratory protection program requirements
• See related: The Sewage Contact Hygiene SOP; Floodwater Exposure for Any Trade; Mold Exposure for Trades Who Are Not Remediators