Oct 2, 2023 - News

Answering your New Orleans saltwater intrusion questions

Estimated timeline for saltwater intrusion into the New Orleans metro area
Data: GOHSEP; Map: Axios Visuals

As New Orleans metro awaits the arrival of the saltwater wedge in the Mississippi River, you've been sending emails asking us what it means.

  • We're answering those questions here.

Catch up quick: A drought across the Mississippi River Valley means salt water from the Gulf of Mexico is coming upriver, threatening drinking water supplies in New Orleans, Jefferson Parish and St. Bernard Parish, which pull their water from the river.

  • Communities farther south in Plaquemines Parish already have salt in their water.
  • After updating its forecasts Oct. 5, The Army Corps of Engineers expects the salt to reach the Algiers water plant in New Orleans by Nov. 23, and it may not reach levels to elicit concern at the Carrollton plant.
  • Officials continue to work on plans to mitigate water disruption.
  • Salt water is not safe to drink for humans or animals. It's also corrosive and could damage pipes.
  • Treatment plants in southeast Louisiana do not have equipment to desalinate water.

Our reporting is clear on one crucial point: No one knows for certain how much salt will get into the local water supply, so it's impossible to know for certain what the impacts of saltwater intrusion will be on infrastructure, homes and businesses in the short- or long-term.

  • But here's what we've discovered so far in answering your questions.

Is my water safe to drink now? Yes, it's fine in New Orleans and Jefferson Parish.

  • Officials are testing salinity levels daily.

Will my water be turned off? No.

  • Mayor LaToya Cantrell and Jefferson Parish officials say it will stay on, no matter the salinity level.

How long will we have salty water? New Orleans officials initially planned for three months, according to NOLA.com | The Times-Picayune.

  • In Plaquemines, it could last six to eight months, New Orleans Sewerage and Water Board deputy general superintendent Steve Nelson says.
  • It's wholly dependent on rainfall.

Water usage at home

How do we remove salt at home? Boiling water will not remove the salt, Louisiana health officials say. Standard fridge water filters and Brita filters won't work either.

  • Reverse osmosis systems work, but they are pricey. Countertop options start around $300 and whole-house filtration systems start around $1,000.

Should we conserve water now? If you're in New Orleans or Jefferson Parish, no.

  • A 24-hour supply of water "flows by our intakes every 1.5 seconds, so there's plenty of fresh water now," says Nelson.
  • But you will want to conserve once the salt arrives.
  • "At that point, if and when we have to dilute, every gallon we don't have to dilute is a gallon I don't have to barge in," Nelson says.

Should we stock up on bottled water now? Leaders say that if you're in New Orleans or Jefferson Parish, buy a gallon or two during your regular grocery run for the next few weeks. But there's no need to rush out and buy every gallon available.

  • "If you are buying and hoarding water in Orleans and Jefferson parishes, you are hurting our neighbors in Plaquemines because when they have to go to New Orleans or Metairie to buy water and there's no water in stock, they have to go even further," says NOLA Ready's Anna Nguyen.

Can salt cause heavy metals in city pipes to leach into the water, contaminating it before it gets to my house? It's possible. Salt does "raise the potential" for leaching, according to the state's top health official, Joseph Kanter.

  • Municipal water lines in New Orleans and Jefferson Parish have an unknown amount of heavy metals, including "lead, galvanized fittings and soldering, all of which raise that risk," but "it's very difficult to predict" what the impacts will be.
  • "Any speculation about impacts is premature," says a SWBNO spokesperson. "We are working diligently with top experts at Louisiana Dept. of Health and the Environmental Protection Agency to prepare to increase our frequency of lead testing and address impacts swiftly with a full range of resources."
  • SWBNO customers can request a free lead testing kit.

How will we know water is safe to drink, even if it doesn't taste salty? New Orleans and Jefferson water officials have increased water testing, and alerts will be sent if the water should health advisories become necessary.

  • The SWBNO has begun sharing water quality testing daily on social media.

Will the water be safe for bathing? The water is currently safe for bathing, but leaders are holding off on giving guidance on that until more details emerge about salinity levels and possible lead contamination.

How will appliances be affected? It's too early to say, Nelson says.

  • "We do know that at really high levels … you can start to see effects on hot water heaters, but we don't know if that's going to be the situation for us," he says.
  • The length of salt exposure is also important to the equation, and we don't know how long that will be.
  • Jefferson Parish President Cynthia Lee Sheng is reaching out to plumbing, HVAC and appliance professionals for expertise. Some longtime appliance repair companies say they don't think the salt will be a problem for dishwashers and washing machines, but acknowledge many unknowns exist.
  • The Louisiana Department of Health suggests calling appliance manufacturers for specifics.

If my home's plumbing or appliances are damaged, will my homeowners' insurance cover that? State law doesn't require the coverage, says a Louisiana Department of Insurance spokesperson, so check with your insurer.

  • Note that damage may take time to become apparent.

Response

If water is distributed, will it be free? Yes.

  • Bottled water will be given out in New Orleans and Jefferson Parish, leaders say. The giveaways will start a few days prior to the forecasted impact date, Nguyen tells Axios New Orleans.
  • The city is exploring distribution locations, such as fire stations, recreation centers, libraries and other city buildings, Nguyen added.
  • In Jefferson Parish, Lee Sheng is working with churches and faith-based organizations to help with distribution.

Will evacuation be necessary? No, not "under the current circumstances," Nguyen says.

Will water treatment plants remove the salt? Water treatment plants in Orleans and Jefferson parishes aren't built to remove salt under normal circumstances, but officials are working on plans to dilute the water before it enters the plants or add desalination technology to the systems.

  • On the East Bank, Orleans and Jefferson parishes will build 10- to 15-mile pipelines to bring clean water from upriver to dilute intakes at its two largest plants: Carrollton and East Jefferson.
  • For smaller plants in Algiers and Gretna, leaders say the water could be made safe through reverse osmosis machines in combination with barging in fresh water to dilute salt at the intakes.
  • Plaquemines Parish has begun installing massive reserve osmosis systems.
Graphic: Kavya Beheraj and Brendan Lynch/Axios
Graphic: Kavya Beheraj and Brendan Lynch/Axios

Didn't we build a sill to stop the intrusion? Yes, the Army Corps of Engineers built an underwater levee, called a sill, over the summer, with construction completed in July.

  • But saltwater overtopped that sill Sept. 20.
  • The Corps began construction Sept. 25 to shore up the sill in a bid to slow the salt water's progression by another 10 to 15 days.
  • All saltwater intrusion forecasts take into account the sill construction.

How far upriver will the saltwater get? A natural feature in the Mississippi River around river mile 115, near Kenner, acts as a sill, much like the underwater levee the Army Corps built downriver.

  • That will slow the salt's progression, but "like our sill, under certain conditions, this would also be overtopped," Army Corps public affairs specialist Matthew Roe says.
  • Ultimately, the progression will depend on the weather forecast as southeast Louisiana awaits higher river levels.

Salt water is at the deepest part of the river, so could water plants draw water from higher up? No. They already pull from the top of the river.

  • Water plant intakes come from the top 3 to 10 feet of the Mississippi River, and the river is between 100 and 200 feet deep, Nelson says.

Why isn't barging already happening for communities further south? The Army Corps barges water "at the request of the state," Roe says, and it began providing water for the Port Sulphur Water Treatment facility Sunday with an initial delivery of a half-million gallons.

  • The Army Corps is also fulfilling requests for reverse osmosis technology in Plaquemines Parish, and it expects to provide barged water for Pointe a la Hache within the coming days.

What are the plans for vulnerable communities? New Orleans officials say communication and distribution plans are in the works to ensure vulnerable communities, including seniors and unhoused people, have access to water updates and any bottled water made available.

  • Jefferson Parish leaders also say they are working with nursing homes, dialysis facilities, home health providers and hospitals to determine needs.

Do other states desalinate water? Yes, Florida and California have water treatment plants that convert seawater to drinking water.

How are local schools preparing? The NOLA Public School system, which is responsible for 43,000 students, is monitoring impacts on drinking water, meal prep and infrastructure.

Infrastructure and industry

If we get salt, how could it damage our water infrastructure? Marc Edwards, a water expert known for his work on the Flint, Michigan, water crisis, tells Verite, "the general rule is that higher salt is worse for metallic pipes," putting both private and public pipes at risk.

  • Age and previous corrosion can create variable impacts, he said, noting that "there's no magic threshold."

Can the system be "flushed out" once the water returns to normal? Once the salt water dissipates, water systems will return to normal.

  • A SWBNO spokesperson says it is "premature to know exactly what type of flushing may be needed."

How will industry be impacted? Cantrell says industry currently is not being asked to limit water usage.

  • As for electricity production, an Entergy New Orleans spokesperson tells Axios New Orleans that the company, which uses water for cooling, does "not foresee any impacts to our operations, equipment, or facilities that generate power."

How will crops, plants and livestock be affected? "Other parts of the world that are incredibly productive for growing fruit and vegetables have been dealing with this for centuries," according to the LSU AgCenter. "We, and our gardens, will be OK. With all things, adaptation is key to resiliency."

  • Belle Chasse citrus farmers say their adult trees will be OK, but they are scrambling to find ways to irrigate their seedlings.
  • The LSU AgCenter offers guidance for managing plants and lawn care at home, as well as expectations for agriculture and livestock.

Still more questions

What's next: We'll keep reporting on saltwater intrusion and finding answers for you.

Of note: Many of the questions have been edited for length and clarity.

  • The Louisiana Department of Health also has an FAQ on health impacts.

Go deeper:

Editor's note: This is a developing story. Please check back for updates.

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