DAYLIGHTING:
1. Illumination of indoor spaces by natural light.
2. A process by which underground pipes are exposed using a hydro-vacuum excavator.
3. Exposing something that has been concealed or covered up.
(Alternative interpretation: “bringing injustice to light”.)
This update includes two good visual and video links describing how lead service line replacement is done.
First the good news: Our municipal water supply has finally been restored to the property line, after the City excavated one section of sidewalk and a small section of asphalt to replace the “public” lead service line (approx. 16 ft / 5 m) and curb-stop valve, installation passed inspection and everything has now been back-filled by us. Our plumber will be back on Wednesday to do some final pressure checks and flushing of lines.
Now, for the techies: There are three most common methods used to access the underground pipes for replacement: conventional digging (backhoe etc.), horizontal boring, and hydro-vacuum excavation. We explored all three options before taking up shovels. (The City used two of those methods in their most recent work.)
Another method used in some areas is “trenchless pulling”, which is very cost-effective for short straight runs.
The links below help to visualize the different processes.
VIDEO
INFOGRAPHIC
Next update will provide more informational references – that list was far too long to attach here.
In the meantime, here is a bit of background for anyone just joining in.
A bit of history: The use of lead as a material for conveying water dates back to Roman times, and there is evidence that even they knew that too much exposure was harmful. By the 1800’s, it was well-known that lead could leach into water and that it was a cumulative toxin for humans, causing a variety of detrimental effects including neurological problems in children, kidney and cardiovascular issues in adults. But it took nearly a century to ban its use in plumbing because of some practical attributes and a strong industry lobby that touted its benefits; it was easy to work with and corrosion-resistant compared to galvanized steel pipes which were used in the early 1900’s. As a result, lead water pipes were used across USA well into the 1950’s and in Canada up to 1970. Lead pipes were used both underground and inside buildings. When copper pipes finally began to displace lead, they were still joined with lead-tin solder, which remained in use until the mid-1980’s. (Lead was also common in paint, bronze fittings, and as a gasoline additive.)
A dose of science: Lead does chemically react naturally over time and that process tends to create a boundary layer that helps reduces leaching and slows further corrosion. In fact, utilities may use chemical additives like phosphates (or use electrical means) as corrosion control - to deliberately maintain a coating on the inside of their lead pipe networks. The result is sometimes erroneously called calcification, because it looks like the scale that forms in a kettle after using “hard” water. (In fact, lead even mimics calcium in our bodies which is why we can absorb it in our bones and organs.) But any oxide or phosphate layer tends to be brittle in comparison to the actual lead itself, so if a pipe is manipulated, the coating can flake away exposing fresh lead beneath. Temperature and acidity of the water can also compromise the coating, causing lead levels in water to spike as infamously happened in Flint Michigan in 2016.
A hint of pragmatism: Because lead pipes are so prevalent, because what remains is largely underground (ie. out of sight/out of mind) and because the replacement of water infrastructure is so expensive, we continue to use them today despite the known risks. Each jurisdiction mandates water quality testing to include for lead content, but the results can be misleading because “acceptable” levels vary by province or state and test samples are often taken at locations determined by the municipality. Health Canada, in 2019, adopted a much-reduced guideline for lead-in-water of 0.005mg/L, but each province sets its own standard. Quebec embraced the new guideline; Ontario did not.
Now, about regulations: In Ontario, Safe Water Drinking Act regulations are enforced by the Ministry of the Environment, Conservation and Parks. Ontario has a threshold for lead in water that is double that of the current national standard of 5 micrograms per litre. Municipalities must report their annual test results, but smaller communities have less stringent requirements. The Province does not provide any budget amounts to municipalities that is specifically intended to address replacement of lead service lines (LSLs), so each municipality sets their own priorities. This province neither mandates that LSLs be replaced, nor even that residents be informed of their presence; everything hinges on reported results of water quality testing by the municipality.
And finally, "old habits die hard": Municipal water is delivered from the treatment facility to individual properties (service addresses) through a network of large (main) pipes and smaller leaders, laterals, or service lines. The portion of a service line that is on a residential property (and as far as the curb-stop valve at the sidewalk) is called the “private” portion, while the portion beyond the property is called the “public” portion. In Brockville, and many other places, public lead service lines are only replaced when a major street infrastructure upgrade is planned – a policy intended to defer cost. This means that when a home-owner replaces their private service line pro-actively, they may still be connected to a public service line made of lead for a long time to come. This outdated practice is referred to as a “partial” service line replacement. Studies made over a decade ago recognized that partial LSL replacements typically caused higher lead levels downstream than before the replacement took place. Because of this, the EPA no longer recommends partial replacements (with few exceptions) but Ontario’s Ministry of Environment… appears to allow them still.