{"id":8006,"date":"2021-06-28T16:37:00","date_gmt":"2021-06-28T14:37:00","guid":{"rendered":"https:\/\/www.idro-elettrica.it\/esperto-risponde\/installing-an-underground-tank-without-a-water-table-a-4-step-quick-guide\/"},"modified":"2026-07-01T09:46:44","modified_gmt":"2026-07-01T07:46:44","slug":"installing-an-underground-tank-without-a-water-table-a-4-step-quick-guide","status":"publish","type":"esperto-risponde","link":"https:\/\/www.idro-elettrica.it\/en\/esperto-risponde\/installing-an-underground-tank-without-a-water-table-a-4-step-quick-guide\/","title":{"rendered":"Installing an Underground Tank Without a Water Table: A 4-Step Quick Guide"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><em>Installing a Tank in the Absence of an Aquifer: If you need to install and backfill a tank where there is no aquifer, here is a clear, step-by-step procedure organized into four phases.<\/em><\/p>\n\n<p class=\"wp-block-paragraph\">Below is a practical guide designed to be read \u201con-site\u201d: what to do, in what order, and with the specified minimum dimensions (clearance from the perimeter, subfloor thicknesses, 50% backfill, and finishing of the top 50 cm).<\/p>\n\n<div class=\"wp-block-rank-math-toc-block\" id=\"rank-math-toc\"><h2>Table of Contents<\/h2><nav><ul><li class=\"\"><a href=\"#interro-serbatoio-senza-falda-da-dove-si-parte\">Installing a Tank Without a Water Table: Where to Start<\/a><\/li><li class=\"\"><a href=\"#franco-perimetrale-e-impostazione-dello-scavo\">Perimeter clearance and excavation layout<\/a><\/li><li class=\"\"><a href=\"#profondita-scavo-e-sottofondo-spessori-minimi-richiesti\">Excavation Depth and Subgrade: Minimum Thickness Requirements<\/a><\/li><li class=\"\"><a href=\"#fase-1-scavo-a-sezione-obbligata-e-formazione-del-sottofondo-di-posa\">Phase 1: Excavation to a specified cross-section and preparation of the subbase<\/a><\/li><li class=\"\"><a href=\"#fase-2-posizionamento-del-serbatoio-e-riempimenti-al-50\">Step 2: Position the tank and fill it halfway<\/a><\/li><li class=\"\"><a href=\"#fase-3-completamento-riempimento-del-serbatoio-e-reinterro-con-sabbia-fine\">Step 3: Complete filling the tank and backfill with fine sand<\/a><\/li><li class=\"\"><a href=\"#fase-4-ultimazione-dellinterro-e-finitura-degli-ultimi-50-cm\">Step 4: Completing the backfilling and finishing the last 50 cm<\/a><\/li><li class=\"\"><a href=\"#riepilogo-operativo-rapido-checklist\">Quick Operational Summary (Checklist)<\/a><\/li><li class=\"\"><a href=\"#conclusione\">Conclusion<\/a><\/li><\/ul><\/nav><\/div>\n\n<h2 id=\"interro-serbatoio-senza-falda-da-dove-si-parte\" class=\"wp-block-heading\">Installing a Tank Without a Water Table: Where to Start<\/h2>\n\n<p class=\"wp-block-paragraph\">Before beginning the installation of the tank without a water table, the operating procedure calls for <strong>creating a perimeter trench at least 50 cm wide<\/strong>, or following the specifications set forth in any plans related to the specific construction site.<\/p>\n\n<p class=\"wp-block-paragraph\">This step is necessary to properly prepare the work area for excavation and all subsequent operations: laying, leveling, backfilling, and reburying.<\/p>\n\n<h2 id=\"franco-perimetrale-e-impostazione-dello-scavo\" class=\"wp-block-heading\">Perimeter clearance and excavation layout<\/h2>\n\n<p class=\"wp-block-paragraph\">The first step is to define the excavation, taking into account:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>A minimum clearance of 50 cm around the perimeter<\/strong>, unless otherwise specified in the design.<\/li>\n\n\n\n<li><strong>Excavation depth<\/strong> calculated to allow for the construction of the subbase with the specified thicknesses.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">At this stage, it\u2019s best to think in terms of a \u201csequence\u201d: excavation is not an end in itself, but must allow for the proper construction of the subbase and subsequent backfilling, without improvisation.<\/p>\n\n<h2 id=\"profondita-scavo-e-sottofondo-spessori-minimi-richiesti\" class=\"wp-block-heading\">Excavation Depth and Subgrade: Minimum Thickness Requirements<\/h2>\n\n<p class=\"wp-block-paragraph\">The <strong>depth of the excavation<\/strong> must be calculated to allow for the construction of <strong>at least<\/strong>:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>30 cm of stabilized material<\/strong><\/li>\n\n\n\n<li><strong>20 cm of sand<\/strong><\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">These two layers serve as the operational reference for the installation subbase. In practical terms, the goal is to prepare a suitable and <strong>properly leveled<\/strong> subbase before installing the tank. <\/p>\n\n<h2 id=\"fase-1-scavo-a-sezione-obbligata-e-formazione-del-sottofondo-di-posa\" class=\"wp-block-heading\">Phase 1: Excavation to specified dimensions and preparation of the subbase<\/h2>\n\n<p class=\"wp-block-paragraph\">In Phase 1, two related activities are performed:<\/p>\n\n<ol class=\"wp-block-list\">\n<li><strong>Execution of the excavation with a fixed cross-section<\/strong>.<\/li>\n\n\n\n<li><strong>Preparation of the subfloor<\/strong>.<\/li>\n<\/ol>\n\n<p class=\"wp-block-paragraph\">In practice, after completing the excavation, the following materials are spread across the bottom:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>at least 30 cm of stabilized material<\/strong><\/li>\n\n\n\n<li><strong>20 cm of sand<\/strong><\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">Everything must be <strong>properly leveled<\/strong> (this marks the completion of Phase 1). In other words: first, prepare the \u201cwork surface\u201d (stabilized base + sand), then move on to handling and installing the tank. <\/p>\n\n<h2 id=\"fase-2-posizionamento-del-serbatoio-e-riempimenti-al-50\" class=\"wp-block-heading\">Step 2: Position the tank and fill it halfway<\/h2>\n\n<p class=\"wp-block-paragraph\">Once the subfloor has been prepared, we move on to the actual installation:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Using an appropriate lifting device<\/strong>, place the tank in its intended position.<\/li>\n\n\n\n<li>Proceed with the <strong>tank leveling<\/strong> operations.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">After leveling, the recommended sequence is as follows:<\/p>\n\n<ol class=\"wp-block-list\">\n<li><strong>Fill the tank to 50% capacity.<\/strong><\/li>\n\n\n\n<li><strong>Begin backfilling the excavation with fine sand<\/strong> until <strong>it is 50% full.<\/strong><\/li>\n<\/ol>\n\n<p class=\"wp-block-paragraph\">Phase 2 focuses on a simple concept: work proceeds \u201cin parallel\u201d on the reservoir and the excavation, bringing both to 50% completion according to the procedure described.<\/p>\n\n<h2 id=\"fase-3-completamento-riempimento-del-serbatoio-e-reinterro-con-sabbia-fine\" class=\"wp-block-heading\">Step 3: Complete filling the tank and backfill with fine sand<\/h2>\n\n<p class=\"wp-block-paragraph\">In Phase 3, the recommendation is:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Finish filling the tank<\/strong>.<\/li>\n\n\n\n<li>Continue <strong>filling with fine sand<\/strong> (backfilling).<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">This phase also includes liaison activities:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Connect all the necessary pipes<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">The idea is to follow a systematic sequence: first, complete the work on the tank (filling it), then make the necessary connections, and finally backfill with fine sand.<\/p>\n\n<h2 id=\"fase-4-ultimazione-dellinterro-e-finitura-degli-ultimi-50-cm\" class=\"wp-block-heading\">Step 4: Completing the backfilling and finishing the last 50 cm<\/h2>\n\n<p class=\"wp-block-paragraph\">Phase 4 involves completing the backfilling of the tank without a water table and finishing the surface.<\/p>\n\n<p class=\"wp-block-paragraph\">The operational guideline is:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Complete filling the excavation with fine sand (Step 3)<\/strong>.<\/li>\n\n\n\n<li><strong>The last 50 cm<\/strong> can be <strong>filled with soil suitable for the desired surface layer (Step 4)<\/strong>.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">This procedure allows you to clearly distinguish between two materials or criteria: first, fine sand to complete the excavation, then the top 50 cm of cohesive soil consistent with the planned surface treatment.<\/p>\n\n<h2 id=\"riepilogo-operativo-rapido-checklist\" class=\"wp-block-heading\">Quick Operational Summary (Checklist)<\/h2>\n\n<p class=\"wp-block-paragraph\">For a quick read, here&#8217;s the complete sequence:<\/p>\n\n<ol class=\"wp-block-list\">\n<li>Clear perimeter space <strong>of at least 50 cm<\/strong> (or as specified in the construction plans).<\/li>\n\n\n\n<li>Excavation to a depth appropriate for the subgrade: <strong>30 cm of stabilized material + 20 cm of sand<\/strong>.<\/li>\n\n\n\n<li>Phase 1: The subgrade has been stabilized and the sand <strong>has been leveled<\/strong>.<\/li>\n\n\n\n<li>Install the tank using the appropriate equipment and <strong>level<\/strong> it.<\/li>\n\n\n\n<li>Step 2: <strong>Fill the tank 50%<\/strong> and backfill with <strong>50% fine sand.<\/strong><\/li>\n\n\n\n<li>Step 3: Complete filling the tank + continue backfilling with fine sand + connect the necessary pipes.<\/li>\n\n\n\n<li>Step 4: Fill the excavation with fine sand and cover <strong>the top 50 cm<\/strong> with suitable soil.<\/li>\n<\/ol>\n\n<h2 id=\"conclusione\" class=\"wp-block-heading\">Conclusion<\/h2>\n\n<p class=\"wp-block-paragraph\">By following these four steps, installing a tank without a water table becomes a well-organized process: excavation and subgrade preparation, installation and leveling, progressive backfilling (to 50% and then completion), backfilling with fine sand, and finishing the top 50 cm.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Installing an above-ground tank: Here is a 4-step procedure, from excavation and subgrade preparation to backfilling with fine sand and finishing. Practical guidelines and work sequence. <\/p>\n","protected":false},"featured_media":8008,"parent":0,"template":"","meta":{"_acf_changed":false,"_angie_page":false,"footnotes":"","_members_access_role":[],"_members_access_error":""},"tags":[780,785,551,779,782,786,778,781,776,783,784,777],"class_list":["post-8006","esperto-risponde","type-esperto-risponde","status-publish","has-post-thumbnail","hentry","tag-background","tag-construction-phases","tag-engineering-insights","tag-excavation","tag-fine-sand","tag-operating-procedures","tag-re-excavation","tag-stabilized","tag-tank-inspection","tag-tank-installation","tag-tank-leveling","tag-underground-tank-without-a-water-table"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde\/8006","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde"}],"about":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/types\/esperto-risponde"}],"version-history":[{"count":0,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/esperto-risponde\/8006\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media\/8008"}],"wp:attachment":[{"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/media?parent=8006"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.idro-elettrica.it\/en\/wp-json\/wp\/v2\/tags?post=8006"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}